Ultimate Set - Electronics

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A half adder adds A. 2 bits B. 3 bits C. 4 bits D. 2 or 3 bits

A half bridge inverter A. needs a 3 wire dc supply B. may use a two wire or 3 wire dc supply C. has higher output voltage if fed from 3 wire dc supply D. has higher efficiency if fed from 3 wire dc supply

B Because capacitor charge is retained.

A half wave diode rectifier has a capacitance input filter. If input voltage is Vm sin ωt, PIV is A. Vm B. 2 Vm C. 3 Vm D. 4 Vm

B A high frequency series inverter has many series inverters in parallel. Only one inverter operates at one time and they operate in fixed sequence.

A high frequency series inverter consists of A. a number of series inverters in series B. a number of series inverters in parallel C. a number of parallel inverters in parallel D. a number of parallel inverters in series

A junction field-effect transistor (JFET) is a ________ device. A. current-controlled B. voltage-controlled C. voltage-current controlled D. None of the above

What semi-conductor device glows red, yellow, or green, depending upon its chemical composition? A light-emitting diode A fluorescent bulb A neon bulb A vacuum diode

A light-emitting diode

A load commutated chopper circuit has A. one thyristor B. two thyristors C. four thyristors D. six thyristors

A logic probe is placed on the input of a digital circuit and the probe lamp blinks slowly, indicating ________. A. that an open or bad logic level exists B. a high level output C. a high-frequency pulse train D. that the supply voltage is low

A logic probe is placed on the output of a digital circuit and the probe lamp is dimly lit. This display indicates ________. A. that an open or bad logic level exists B. a high level output C. a high-frequency pulse train D. that the supply voltage is low

A logic signal experiences a delay in going through a circuit. The two propagation delay times are defined as: A. tPLH and tPHL. B. tDLH and tDHL. C. tHPL and tlph. D. tLDH and tHDL.

A logical expression Y = A + ¬AB is equal to A. Y = AB B. Y = ¬AB C. Y = ¬A + B D. Y = A + B

A memory system of size 16 k bytes is to be designed using memory chips which have 12 address lines and 4 data lines each. The number of such chips required to design the memory system is A. 2 B. 4 C. 8 D. 18

A mini-program that can be used repeatedly, but is programmed only once is called a(n) ________. A. string B. subroutine C. interrupt D. processor control

B Mod 4 counter has 4 states, 0 to 3.

A mod 4 counter will count A. from 0 to 4 B. from 0 to 3 C. from any number n to n + 4 D. none of the above

A monostable 555 timer has the following number of stable states: A. 0 B. 1 C. 2 D. 3

A monotonicity error in a DAC will show up as an incorrect analog output ________. A. only for higher value inputs B. only for lower value inputs C. only for certain (scattered) inputs D. for all inputs

A negative feedback can be of A. 2 types B. 3 types C. 4 types D. only 1 type

A p-n junction diode has A. low forward and high reverse resistance B. a non-linear v-i characteristics C. zero forward current till the forward voltage reaches cut in value D. all of the above

A periodic voltage has following value for equal time intervals changing suddenly from one value to next... 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, -5, -10 etc. Then rms value of the waveform is A. 31 V B. 32 V C. insufficient data D. none of these

A port can be ________. A. strictly for input B. strictly for output C. bidirectional D. all of the above

A presettable counter with 4 flip flops can start counting from A. 0000 B. 1000 C. any number from 0000 to 1000 D. any number from 0000 to 1111

B Reactor is used only for circulating current mode.

A reactor is used in a dual converter operating in non-circulating current mode. A. True B. False

A register in the microprocessor that keeps track of the answer or results of any arithmetic or logic operation is the: A. stack pointer B. program counter C. instruction pointer D. accumulator

D Almost whole of reverse voltage is across depletion layer.

A reverse voltage of 18 V is applied to a semiconductor diode. The voltage across the depletion layer is A. 0 V B. 0.7 V C. about 10 V D. 18 V

A ring counter with 5 flip flops will have A. 5 states B. 10 states C. 32 states D. infinite states

A If fOL is less than fOH, a passband will exist from fOL to fOH .

A second order active bandpass filter can be obtained by cascading LP second order filter having higher cut off frequency fOH with a second order HP filter having lower cut off frequency fOL provided A. fOL < fOH B. fOL > fOH C. fOH = fOL D. fOH < 0.5 fOL

B It operates only in quadrant.

A semi converter operates in two quadrants. A. True B. False

A semiconductor diode is biased in forward direction and carrying current I. The current due to holes in p material is A. I B. 0 C. less than I D. 0.5

A semiconverter feeding an RLE load operates in A. first quadrant only B. first and second quadrants C. first and fourth quadrants D. first and third quadrants

A separately excited dc motor is run from a dc source through a chopper. At 600 rpm and rated torque, the duty cycle of chopper is 0.8. At 600 rpm and half the rated torque, the duty cycle is likely to be A. 0.9 B. 0.8 C. 0.75 D. 0.6

A settable flip-flop's normal starting state when power is first applied to a circuit is always the ________ state. A. reset B. set C. toggle D. dual

A short circuit has a(n) _____ V drop across its terminals, but the current is limited only by the surrounding network. A. 5 B. 0 C. 1 D. ∞

A silicon (PN) junction at a temperature of 20°C has a reverse saturation current of 10 pico Ampere. The reverse saturation current at 40°C for the same bias is approximately. A. 30 pA B. 40 pA C. 50 pA D. 60 pA

C Anode, cathode, anode gate and cathode gate.

A silicon controlled switch has : A. 2 leads B. 3 leads C. 4 leads D. 5 leads

A single phase bridge type cycloconverter uses eight thyristors. A. True B. False

A single phase cycloconverter feeds a resistance heating load. The heating power is provided by A. only the fundamental component of output wave B. only higher harmonics in the output wave C. both fundamental and higher harmonics in the output wave D. either (a) or (b)

A single phase cycloconverter with centre tapped input transformer requires A. 2 thyristors B. 4 thyristors C. 8 thyristors D. either 2 or 4 thyristors

A single phase dual converter consists of A. two fully controlled converters connected in parallel B. two fully controlled converters connected in antiparallel C. two fully controlled semiconverters connected in antiparallel D. two fully controlled semiconverters connected in parallel

B Conduction occurs only during 50% of wave.

A single phase electric heater uses phase controlled thyristors. The firing angle is 90°. The degree of heating is A. 25% of maximum B. 50% of maximum C. 75% of maximum D. none of the above

A single phase full bridge inverter for R-L loads needs A. 4 thyristors B. 4 thyristors and 4 diodes C. 4 thyristors and 2 diodes D. 8 thyristors

A single phase full converter can operate in A. 4 quadrants B. 3 quadrants C. 2 quadrants D. 1 quadrant

A Output voltage is maximum if a = 0 and is minimum if a = 180°.

A single phase full converter gives maximum and minimum output voltage at firing angles of A. 0 and 180° respectively B. 180° and 0° respectively C. 0 and 90° respectively D. 90° and 0° respectively

C because load is R - L.

A single phase full wave regulator feeds R-L load. The best gating signal is A. short duration pulses B. long duration pulses C. pulse train D. either (a) or (b)

A single phase full wave regulator feeds a resistive load. The firing angle of thyristors is 90°. The input power factor is A. 1 B. 0.707 lagging C. 0.5 lagging D. 0.2 lagging

C During the period of overlap all the four thyristors conduct and load is effectively short-circuited. Output voltage is zero.

A single phase fully controlled bridge rectifier is fed by a source having inductance. The output voltage during overlap period is A. Vm B. 0.5 Vm C. zero D. 0.5 Vm - voltage drop across inductance

A single phase half bridge inverter required to feed R-L loads needs A. 2 thyristors B. 4 thyristors C. 2 thyristors and two diodes D. 4 thyristors and 4 diodes

B Free wheeling diode is forward biased only when SCR is reverse biased.

A single phase half wave controlled rectifier circuit has an R-L load. A freewheeling diode is also in the circuit. When freewheeling diode is conducting the SCR A. is forward biased B. is reverse biased C. may be forward biased or reverse biased D. forward biased initially but reverse biased afterwards

C Before triggering the whole of applied voltage is across SCR and load current is zero.

A single phase half wave converter is feeding a resistive load. Just before triggering, the voltage across thyristor is A. zero B. about 1 V C. same as input voltage D. twice the input voltage

A single phase half wave converter is feeding a resistive load. Output dc power is Pdc and total power delivered to load is Pac then A. Pdc = Pac for all values of firing angles B. Pdc = Pac if firing angle is less than 180° C. Pdc < Pac for all values of firing angles D. Pdc < Pac if firing angle is less than 180°

B Thyristor can conduct only when it is forward biased. This occurs only when v > 50 V.

A single phase half wave converter is used to charge a battery of 50 V. The thyristor is continuously fired by dc signal. Input voltage is v = Vm sin ωt. The thyristor will conduct A. from 0 to 180° B. when v > 50 V C. from 0 to 90° D. When v < 50 V

A single phase half wave rectifier circuit has a free wheeling diode. The free wheeling diode will conduct only if A. load is purely resistive B. load is purely inductive C. load is combination of R and L D. load is purely inductive or combination of R and L

A single phase half wave rectifier is feeding a resistive load. As firing angle is increased A. dc output voltage and rms output voltage decrease in the same proportion B. dc output voltage and rms output voltage decrease C. dc output voltage and rms output voltage increase D. dc output voltage and rms output voltage increase in the same proportion

A single phase half wave rectifier is feeding a resistive load. When a = 0, dc output voltage is 127 V. When a = 30°, the dc output voltage will be about A. 127 V B. 120 V C. 110 V D. 100 V

C Regulation is possible only in positive half cycle.

A single phase half wave regulator uses A. 2 diodes and 2 thyristors B. 2 thyristors C. 1 diode and 1 thyristor D. 2 diodes

A Freewheeling diode conducts only when load is inductive. If load is purely resistive free wheeling diode does not come into operation.

A single phase semiconverter has a freewheeling diode. If the firing angle is a and the load is purely resistive, the periods of conduction and freewheeling respectively are A. pie - a and 0 B. pie - a and a C. pie + a and 0 D. pie + a and a

A single phase semiconverter is feeding a highly inductive load and has a freewheeling diode across the load. The waveshape of input current is A. sinusoidal B. rectangular C. sinusoidal or rectangular D. triangular

B When freewheeling diode conducts output current exists but output voltage is zero.

A single phase semiconverter is feeding a highly inductive load and has freewheeling diode across the load. The waveshapes of output voltage and output current A. are similar B. are not similar C. may be similar or dissimilar D. are similar only if firing angle is zero

B Freewheeling diode conducts for a° in each half cycle.

A single phase semiconverter is feeding a highly inductive load. The circuit has a freewheeling diode across the load and firing angle is a. During one cycle of input voltage, the total duration of conduction of freewheeling diode is A. a B. 2 a C. 4 a D. 0.5 a

A single phase semiconverter is supplying RLE load and has a freewheeling diode across the load. The firing angle is a. The freewheeling diode conducts for A. a° in each half cycle B. (p - a)° in each cycle C. a° in one full cycle D. (p + a)° in each half cycle

A Series connection increases the voltage.

A single phase series converter is used for A. high voltage output B. high current output C. high voltage and high current output D. improving the circuit efficiency

B Since output frequency is 2f, one half wave of input must equal one full wave of output.

A single phase step up cycloconverter changes 50 Hz to 100 Hz. Then one half wave of input will give rise to A. one half wave of output B. one full wave of output C. two full waves of output D. either (b) or (c)

A standard TTL circuit with a totem-pole output can sink, in the LOW state (IOL(max)), ________. A. 16 mA B. 20 mA C. 16 uA D. 20 uA

A standard logic device can be connected on a bus system as an open-collector logic device by connecting each output to a ________. A. discrete transistor B. 10 k series resistor C. light-emitting diode D. CMOS buffer

A static excitation system uses A. transformer and thyristors B. transformer and ac exciter C. dc exciter and ac exciter D. transformer and dc exciter

B It can be turned on by positive gate pulse and turned off by negative gate pulse. It is minority carrier device. It can be manufactured in high current and high voltage ratings and its on state voltage drops is low.

A static induction thyristor A. is a majority carrier device B. is a minority carrier device C. either a majority carrier or minority carrier device D. has a total number of 2 leads

A step down cycloconverter has an input frequency f. If it uses natural commutation, the output frequency A. must be a sub-multiple of input frequency B. can be any frequency C. must be an even sub-multiple of input frequency D. must be an odd sub-multiple of input frequency

A step up chopper can give an output voltage A. higher than input voltage B. lower than input voltage C. both higher and lower input voltage D. all of the above

A string of series connected thyristors needs equalising circuit to A. ensure proper firing B. ensure proper current division C. ensure proper voltage division D. none of the above

A surge voltage A. has very high magnitude and very long duration B. has very high magnitude and very small duration C. has very high magnitude and very small duration and can be positive or negative D. can be only positive

A three state switch has three outputs. These are A. low, low and high B. low, high, high C. low, floating, low D. low, high, floating

A thyristor circuit is feeding an R-L load. The turn on time can be reduced by A. decreasing R B. decreasing L C. increasing L D. decreasing R and L together

C Inductive load increases the turn on time.

A thyristor has a turn on time of 6 μs. If the anode circuit is inductive, the turn on time will be A. 6 μs B. less than 6μs C. more than 6 μs D. either 6 μs or less

B With zero gate current, conduction can be started only if forward voltage exceeds breakover voltage.

A thyristor has its gate current zero. To start conduction the forward voltage must exceed A. about 0.5 V B. forward breakover voltage C. on state voltage D. peak working off state forward voltage

A thyristor is reverse biased. A positive gate pulse is applied. The thyristor A. will be turned on B. may or may not turn on C. will not turn on D. will turn on after sometime

A thyristor needs protection against A. high DV/DT B. high DI/DT C. both high DV/DT and high DI/DT D. either high DV/DT or high DI/DT

A transistor can be checked using a(n) _____. A. curve tracer B. digital meter C. ohmmeter D. any of the above

C Derating improves reliability but does not affect maximum power dissipation.

A transistor has a maximum power dissipation of 350 mW at an ambient temperature of 25°C. If derating factor is 2 mW/°C, the maximum power dissipation for 40°C ambient temperature is A. 300 mW B. 330 mW C. 350 mW D. 380 mW

A transistor has two p-n junctions. The batteries should be connected such that A. both junctions are forward biased B. both junctions are reverse biased C. one junction is forward biased and the other is reverse biased D. none of the above

B gm is about 0.1 x 10^-3 siemens.

A typical value of gm for a FET is about 25 μs. A. True B. False

A universal shift register can shift A. from left to right B. from right to left C. both from left to right and right to left D. none of the above

A Its voltage dependent capacitance is used for tuning.

A varactor diode is used for A. tuning B. rectification C. amplification D. rectification and amplification

D No current can flow through virtual ground. However voltage is zero.

A virtual ground is a ground for A. voltage B. current C. both voltage and current D. voltage but not for current

B It is a high voltage device. However current has to be low since diode rated currents are low.

A voltage multiplier circuit, using diodes and capacitors is suitable for A. high voltage high current device B. high voltage low current device C. low voltage low current device D. low voltage high current device

A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000 Ω. The voltage across the load resistance is zero. It indicates that A. diode is short circuited B. diode is open circuited C. resistor is open circuited D. diode is either o.c or s.c

A(n) _____ is the simplest of semiconductor devices. A. diode B. transistor C. operational amplifier D. SCR

A(n) ________ can be used to check the condition of an FET. A. digital display meter (DDM) B. ohmmeter (VOM) C. curve tracer D. All of the above

AB + A¬B = A. B B. A C. 1 D. 0

C For non-inverting terminal input, output is in phase with input. For inverting terminal input, output is 180° out of phase with input. If inputs have 180° phase difference, outputs will be in phase and additive

Ac signals are given to both inverting and non-inverting terminals of an op-amp. When will the output maximum A. when the phase difference between the inputs is 0° B. when the phase difference between the inputs in 90° C. when the phase difference between the inputs is 180° D. when the phase difference between the inputs is 0 or 180°

All amplifiers should have at least ________ terminals with ________ terminal(s) controlling the flow between ________ other terminal(s). A. 2, 1, 1 B. 3, 1, 2 C. 3, 2, 1 D. 3, 0, 3

All computer programs for a machine are called: A. software B. firmware C. hardware D. none of the above

B Line commutated inverters are also used especially in HVDC.

All inverters use forced commutation. A. True B. False

All other parameters remaining the same, a 3 phase bridge inverter with 180° mode of operation A. has the same peak thyristor current as in 120° mode of operation B. has higher peak thyristor current than in 120° mode of operation C. has lower peak thyristor current than in 120° mode of operation D. any of the above

An 8 bit DAC has a full scale output of 2 mA and full scale error of ± 0.5%. If input is 10000000 the range of outputs is A. 994 to 1014 μA B. 990 to 1020 μA C. 800 to 1200 μA D. none of the above

D In serial shift register one pulse is needed to store each bit.

An 8 bit binary number is to be entered into an 8 bit serial shift register. The number of clock pulses required is A. 1 B. 2 C. 4 D. 8

D In a parallel in register only one pulse is needed to enter data.

An 8 bit data is to be entered into a parallel in register. The number of clock pulses required is A. 8 B. 4 C. 2 D. 1

An 8 bit transistor register has output voltage of low-high-low-high-low-high-low-high. The decimal number stored is A. 105 B. 95 C. 85 D. 75

An ADC that compares each bit, one at a time, with the input analog signal is a ________. A. single-slope ramp converter B. dual-slope ramp converter C. successive-approximation converter D. tracking converter

An ADC that uses an up/down counter (and other devices) to follow changes in the input analog signal is a ________. A. single-slope ramp converter B. dual-slope ramp converter C. successive-approximation converter D. tracking converter

B All AND inputs must be 1 and inhibit 0 for output to be 1.

An AND gate has two inputs A and B and one inhibit input 3, Output is 1 if A. A = 1, B = 1, S = 1 B. A = 1, B = 1, S = 0 C. A = 1, B = 0, S = 1 D. A = 1, B = 0, S = 0

An LED has a rating of 2 V and 10 mA. It is used along with 6V battery. The range of series resistance is A. 0 to 200 Ω B. 200 - 400 Ω C. 200 Ω and above D. 400 Ω and above

An OL indication on an advanced digital meter indicates ________ while checking a transistor. A. forward bias B. reverse bias C. definitely a defective transistor D. None of the above

An OR gate has 4 inputs. One input is high and the other three are low. The output A. is low B. is high C. is alternately high and low D. may be high or low depending on relative magnitude of inputs

C One RC combination can give a phase shift of less them 90°. Therefore 3 RC combinations are required for 180° phase shift.

An RC oscillator uses A. one RC combination B. two RC combinations C. at least three RC combinations D. either (a) or (b)

C Especially high dv/dt during switching.

An RC snubber circuit is used to protect a thyristor against : A. false triggering B. failure to turn on C. switching transients D. failure to commutate

B Duration of gate pulse should be slightly more than turn time of SCR.

An SCR has a turn on time of 4 μs. The gate pulse should have a duration of about A. 2 μs B. 5 μs C. 20 μs D. 50 μs

An SCR is triggered at 40° in the positive half cycle only. The average anode current is 50 A. If the firing angle is changed to 80°, the average anode current is likely to be A. 50 A B. 25 A C. less than 50 A but more than 25 A D. less than 25 A

An SCR is triggered at 80° in the positive half cycle, only. The rms anode current is 25 A. If the firing angle is changed to 160°, the rms current is likely to be A. 25 A B. 12.5 A C. less than 25 A D. less than 12.5 A

An SUS is A. exactly similar to SCR but with higher rating B. similar to UJT C. PUT and avalanche diode connected in anti parallel D. SCR and avalanche diode connected in parallel

An air gap provided in the iron core of an inductor prevents A. flux leakage B. hysteresis loss C. core saturation D. heat generation

An amplifier has a large ac input signal. The clipping occurs on both the peaks. The output voltage will be nearly a A. sine wave B. square wave C. triangular wave D. (a) or (c)

B A feedback amplifier is stable if loop gain is less than unity. More less, more stable, hence β will be more stable.

An amplifier with loop gain Aβ will be more stable for value of Aβ as A. 0.95 B. 0.7 C. 1.2 D. 1.5

An astable multivibrator requires: A. balanced time constants B. a pair of matched transistors C. no input signal D. dual J-K flip-flop

An electric heater is controlled by thyristors through on-off control. If a = 0.4, the heating is A. 16% maximum B. 40% of maximum C. 60% of maximum D. 84% of maximum

An electron rises through a voltage of 100 V. The energy acquired by it will be A. 100 eV B. 100 joules C. (100)^1.2 eV D. (100)^1.2 joules

An example of a pnp silicon transistor is a 2N4123. A. True B. False

An example of a unidirectional bus in a microcomputer system is the ________. A. address bus B. data bus C. control bus D. all of the above

B It has resistance in feedback path.

An exponential amplifier has diode in feedback path. A. True B. False

C When pentavalent impurity is added, the number of fresh electrons is very large as compared to number of holes.

An extrinsic semiconductor sample has 6 billion silicon atoms and 3 million pentavalent impurity atoms. The number of electrons and holes is A. 3 million each B. 6 billion each C. 3 million free electrons and very small number of holes D. 3 million holes and very small number of free electrons

B An ideal op-amp has infinitely fast slew rate.

An ideal op-amp has zero slew rate. A. True B. False

An ideal power supply has A. zero internal resistance B. very high internal resistance C. high output resistance D. both (b) and (c)

An ideal rectifier should have A. 100% efficiency, zero ripple factor, zero harmonic factor and unity displacement factor B. 100% efficiency, zero tipple factor, zero harmonic factor and zero displacement factor C. 100% efficiency, zero ripple factor, unity harmonic factor and unity displacement factor D. 100% efficiency, unity ripple factor, zero harmonic factor and unity displacement factor

B Increase of ambient temperature means that heat dissipation is slower.

An increase in ambient temperature means that maximum power rating of transistor A. will increase B. will decrease C. may increase or decrease D. may increase or remain the same

An increase in junction temperature of a semiconductor diode A. causes a small increase in reverse saturation current B. causes a large increase in reverse saturation current C. does not affect reverse saturation current D. may cause an increase or decrease in reverse saturation current depending on rating of diode

B With increase in temperature width of depletion layer decreases.

An increase in temperature increases the width of depletion layer. A. True B. False

An increase in temperature of a semiconductor can result in a _____ in the number of free electrons in the material. A. substantial increase B. substantial decrease C. slight decrease D. no change

An incremental model of a solid state device is one which represents the A. ac property of the device at desired operating point B. dc property of the device at all operating points C. complete ac and dc behaviour at all operating points D. ac property of the device at all operating points

An indication of cutoff in an NPN bipolar transistor is that the: A. collector current is maximum B. collector-to-emitter voltage equals zero C. base-to-emitter voltage equals 0.7 V D. collector to emitter appears to be open

An interrupt method that requires the CPU to test each peripheral device in sequence is called ________. A. vectored I/O B. polled I/O C. programmed interrupt D. interrupt-driven I/O

An npn transistor has a Beta cutoff frequency fβ of 1 MHz, and a common emitter short circuit low frequency current gain β0 of 200. It unity gain frequency fT and the alpha cut off frequency fa2 respectively are A. 200 MHz, 201 MHz B. 200 MHz, 199 MHz C. 199 MHz, 200 MHz D. 201 MHz, 200 MHz

An offset error in a DAC will show up as an incorrect analog output ________. A. only for higher value inputs B. only for lower value inputs C. only for certain (scattered) inputs D. for all inputs

An op-amp has very ________. A. high voltage gain B. high input impedance C. low output impedance D. all of the above

B Since common mode signal is reduced to zero, CMRR is infinite.

An op-amp has zero gain for common mode inputs. Then CMRR = A. zero B. infinite C. high D. low

An open circuit can have any voltage across its terminals, but the current is always _____ A. A. 5 B. 0 C. 1 D. ∞

An open collector output can ________ current, but it cannot ________. A. sink, source current B. source, sink current C. sink, source voltage D. source, sink voltage

An open-collector TTL gate ________. A. can source current but cannot sink current B. can sink current but cannot source current C. cannot source or sink current D. can sink more current than a standard TTL gate

An open-collector output requires ________. A. a pull-down resistor B. a pull-up resistor C. no output resistor D. an output resistor

An open-drain gate is the CMOS counterpart of ________. A. an open-collector TTL gate B. a tristate TTL gate C. a bipolar junction transistor D. an emitter-coupled logic gate

B Positive feedback is necessary for sustained oscillations

An oscillator requires an amplifier A. with negative feedback B. with positive feedback C. with either positive or negative feedback D. none of the above

Any electron that has left its parent atom has _____ energy state relative to any electron in the atomic structure. A. the same B. a lower C. a higher D. an undefined

As VGS becomes ________ negative, the slope of each curve in the characteristics becomes ________ horizontal corresponding with an increasing resistance level. A. less, more B. more, less C. more, more D. None of the above

As a general rule, the lower the value of the speed-power product, the better the device because of its: A. long propagation delay and high power consumption B. long propagation delay and low power consumption

A Tunnel diode has heavily doped p and n regions.

As comparated to an ordinary p-n diode, the extent of impurity atoms in a tunnel diode A. is more B. is less C. may be more or less D. is almost the same

As compared to BJT, MOSFET has A. lower switching losses and higher conduction losses B. higher switching losses and higher conduction losses C. higher switching losses and lower conduction losses D. lower switching losses and lower conduction losses

D For bridge rectifier, peak inverse voltage is equal to peak value of ac voltage while for the circuit using centre tapped transformer peak inverse voltage is 2 Em.

As compared to a full wave diode rectifier circuit using centre tapped transformer, the bridge diode rectifier circuit has the main advantage of A. higher current carrying capacity B. higher efficiency C. lower ripple factor D. lower PIV

As compared to a p-n junction diode A. a schottky diode has lower cut in voltage and lower reverse saturation current B. a schottky diode has higher cut in voltage and higher reverse saturation current C. a Schottky diode has lower cut in voltage and higher reverse saturation current D. a schottky diode has higher cut in voltage and lower reverse saturation current

C This is due to high electron concentration in metals.

As compared to an ordinary semiconductor diode, a Schottky diode A. has higher reverse saturation current B. has higher reverse saturation current and higher cut in voltage C. has higher reverse saturation current and lower cut in voltage D. has lower reverse saturation current and lower cut in voltage

As regards single phase dual converter A. the change in operation from one quadrant to the other is faster in non-circulating current mode B. the change in operation from one quadrant to the other is faster in circulating current mode C. the time response to change in operation from one quadrant to other is the same in both the modes D. the time response to change in operation from one quadrant to the other may be faster in any of the two modes

B Therefore, conductivity increases.

As temperature increases A. the forbidden energy gap in silicon and germanium increase B. the forbidden energy gap in silicon and germanium decrease C. the forbidden energy gap in silicon decreases while that in germanium decreases D. the forbidden energy gap in silicon increases while that in germanium decreases

B With increase in temperature, the forbidden gap decreases.

As temperature increases the forbidden gap in silicon increases. A. True B. False

As temperature increases the number of free electrons and holes in an intrinsic semiconductor A. increases B. decreases C. remains the same D. may increase or decrease

As the firing of a thyristor is delayed, the output voltage of a controlled rectifier decreases. A. True B. False

As the ratio Rf/RL increases the efficiency of a rectifier increases. A. True B. False

Assertion (A): A DIAC has four layers but only two terminals. Reason (R): A DIAC can conduct in both directions. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A GTO can be turned on and turned off by gate pulses Reason (R): A GTO can be turned off by negative gate pulse. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

A Since commutation circuit is not required, GTO circuit is compact.

Assertion (A): A GTO circuit is more compact than SCR circuit Reason (R): A GTO can be turned off by negative gate pulse. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A JFET behaves as a resistor when VGS < VP. Reason (R): When VGS < VP, the drain current in a JFET is almost constant. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

A Since a TRIAC can conduct in both directions it is bi directional SCR.

Assertion (A): A TRIAC is a bidirectional SCR. Reason (R): A TRIAC is a four layers 3 terminal device and can conduct in both directions. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A class C chopper can operate in first and second quadrants Reason (R): A class B chopper operates only in second quadrant. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A cycloconverter may be line commutated or forced commutated Reason (R): A step up cycloconverter requires forced commutation. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A decrease in temperature increases the reverse saturation current in a p-n diode. Reason (R): When a diode is reverse biased surface leakage current flows. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

C Demultiplexer requires NOT gates also in addition to AND gates.

Assertion (A): A demultiplexer can be used as a decoder. Reason (R): A demultiplexer can be built by using AND gates only. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

C In circulating current dual converter both converters operate together.

Assertion (A): A dual converter may be circulating current type or non circulating current type. Reason (R): In circulating current dual converter only one converter can be operated at one time. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A fully controlled bridge converter can operate in first and fourth quadrant. Reason (R): A semi converter is cheaper than a full converter. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A half wave controlled rectifier has poorer efficiency and higher ripple factor than a full wave controlled rectifier. Reason (R): The use of a freewheeling diode in half wave controlled rectifier circuit improves the waveform of load current and circuit power factor. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

A The charging current may cause triggering.

Assertion (A): A high dv/dt may cause triggering of a thyristor. Reason (R): A high dv/dt results in charging current in the thyristor. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): A high junction temperature may destroy a diode. Reason (R): As temperature increases the reverse saturation current increases. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): A multiplexer can be used for data routing. Reason (R): A multiplexer has one input and many outputs. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

Assertion (A): A p-n junction has high resistance in reverse direction. Reason (R): When a reverse bias is applied to p-n junction, the width of depletion layer increases. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): A transistor has lower voltage drop during conduction as compared to thyristor Reason (R): Transistors are manufactured in very high voltage and current ratings. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

C Transistors are used but not very widely.

Assertion (A): A transistor requires a continuous base signal for conduction but a thyristor requires a gate pulse. Reason (R): Transistor find widespread application in power electronic circuits. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): An ac regulator uses natural commutation Reason (R): An ac regulator can be used for static on load tap changing of transformer. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

D Ideal rectifier should have zero harmonic factor and unity displacement factor.

Assertion (A): An ideal rectifier should have unity harmonic factor Reason (R): An ideal rectifier should have unity displacement factor. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

D Some inverters require forced commutation.

Assertion (A): An inverter does not require forced commutation Reason (R): A series inverter is a forced commutation inverter. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): An op-amp has high voltage gain, high input impedance and low output impedance Reason (R): Negative feedback increases output impedance A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

Assertion (A): CE amplifier is the most widely used BJT amplifier Reason (R): CE amplifier has zero phase difference between input and output A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

D CMOS has high packing density but low speed.

Assertion (A): CMOS devices have very high speed. Reason (R): CMOS devices have very small physical size and simple geometry. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

Assertion (A): Chopper always requires forced commutation Reason (R): Morgan chopper uses a saturable reactor. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

A Since transistors in ECL do not enter saturation state, switching is fast.

Assertion (A): ECL gate has very high speed of operation. Reason (R): Transistors in ECL do not go into saturation region. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

A Since the characteristics is non-linear, graphical analysis is needed.

Assertion (A): For large signal variations an amplifier circuit has to be analysed graphically Reason (R): The output characteristics of a transistor is nonlinear. A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

Assertion (A): Gate triggering is the most commonly used method for triggering of an SCR. Reason (R): Even a small gate current is sufficient to turn on an SCR. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): Germanium is more commonly used than silicon. Reason (R): Forbidden gap in germanium is less than that in silicon. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

C If duty cycle is low, current may become discontinuous.

Assertion (A): If the duty cycle of chopper is low the current would not become discontinuous Reason (R): If the time constant L/R of the load in chopper is low the current may become discontinuous. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): In CE amplifier the emitter is at ground potential for ac signals Reason (R): A CE amplifier has near unity voltage gain A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

Assertion (A): In a BJT base current is very small. Reason (R): In a BJT recombination in base region is high. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): In a BJT, the base region is very thick. Reason (R): In p-n-p transistor most of holes given off by emitter diffuse through the base. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

B Since output consists of half sinusoids, output frequency is twice the input frequency.

Assertion (A): In a full wave rectifier output the lowest ac component is at twice the input frequency Reason (R): In a full wave rectifier, the output waveform consists of half sinusoids A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

Assertion (A): In an RC coupled amplifier the junction capacitances can be neglected at low frequencies but not at high frequencies Reason (R): Capacitive reactance is inversely proportional to frequency. A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

C Large value capacitor cannot be fabricated on a chip.

Assertion (A): In an op-amp the voltage gain and band width can be adjusted as per requirement Reason (R): Large value capacitor can also be fabricated on a chip A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

Assertion (A): In class C amplifier the efficiency is more than that for other classes of amplifiers Reason (R): In class C amplifier we can get high efficiency over a wideband A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

A Increase of ambient temperature lowers the heat dissipation capacity. Therefore derated operation of BJT is necessary lest BJT should be destroyed.

Assertion (A): In design of circuit using BJT, a derating factor is used. Reason (R): As the ambient temperature increases, heat dissipation becomes slower. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): Inverters and choppers use fast switching thyristors Reason (R): Fast switching SCR has low turn off time. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): Light triggering is very suitable for HVDC transmission. Reason (R): Light triggering has the advantage of complete electrical isolation of gate circuit. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): McMurray Bredford half bridge inverter uses complementary commutation Reason (R): Three phase inverter can have two modes of operation. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): Negative feedback reduces the bandwidth of an amplifier Reason (R): Negative feedback stabilizes the gain of an amplifier A. Both A and R are correct and R is correct explanation for A B. Both A and R are correct but R is not correct explanation for A C. A is correct R is wrong D. A is wrong R is correct

A Lower work function leads to higher emission current. Therefore oxide coated cathodes are commonly used.

Assertion (A): Oxide coated cathodes are very commonly used. Reason (R): Work function of oxide coated cathode is 1 eV whereas it is 4.5 eV for pure tungsten. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

D Power transistor does not have hight dv/dt rating.

Assertion (A): Power transistor has lower switching time than SCR Reason (R): Power transistor has greater switching time than SCR A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): SUS is a PUT and avalanche diode connected between gate and cathode Reason (R): SBS has two SUS inbuilt together and connected in anti-parallel A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

A Wider forbidden gap in silicon makes it less sensitive to temperature than germanium.

Assertion (A): Silicon is preferred over germanium in manufacture of semiconductor devices. Reason (R): Forbidden gap in silicon is more than that in germanium. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

A Since voltage across capacitor cannot change instantaneously it protects SCR against high DV/DT

Assertion (A): Snubber circuit has an RC series circuit in parallel with SCR Reason (R): Voltage across a capacitor can not change instantaneously. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

C In Schottky TTL storage time is reduced.

Assertion (A): TTL is a very popular logic in SSI and MSI category. Reason (R): In Schottky TTL the power dissipation is less than in ordinary TTL. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

Assertion (A): The amount of photoelectric emission depends on the intensity of incident light. Reason (R): Photo electric emission can occur only if frequency of incident light is less than threshold frequency. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

A Low work function permits easy emission.

Assertion (A): The behaviour of FET is similar to that of a pentode. Reason (R): FETs and vacuum triode are voltage controlled devices. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

B A refers to type semiconductor while R refers to n type semiconductor. Both A and R are correct but independent.

Assertion (A): The conductivity of p type semiconductor is higher than that of intrinsic semiconductor. Reason (R): The addition of donor impurity creates additional energy levels below conduction band. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): The forward resistance of a p-n diode is not constant. Reason (R): The v-i characteristics of p-n diode is non-linear. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

A Gate current in the form of pulses is commonly used because gate losses are low.

Assertion (A): The gate current of an SCR is always in the form of pulses. Reason (R): The gate losses, in pulse triggering, are low. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): The output of a NOR gate is equal to the complement of OR of input variables. Reason (R): A XOR gate is a universal gate. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

Assertion (A): The output voltage of an inverter can be controlled by PWM technique Reason (R): In a current source inverter the input current is constant. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): The reverse saturation current in a semiconductor diode is 4nA at 20°C and 32 nA at 50°C. Reason (R): The reverse saturation current in a semiconductor diode doubles for every 10°C rise in temperature. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

A Since duration of surge current is small, the associated energy is small.

Assertion (A): The surge current which an SCR can withstand is much higher than rms on state current. Reason (R): The duration of surge current is very small. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): The turn on time of SCR is about 1 to 4 ms. Reason (R): The turn off time of SCR is about 10 to 300 ms. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): Thyristors can be used in controlled heating, excitation systems of alternators, speed control of motors and HVDC Reason (R): A static var system using thyristors is very commonly used in high voltage ac systems. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

C Outputs of tristate logic are 0, 1 and high impedance state.

Assertion (A): Tristate logic is used for bus oriented systems Reason (R): The outputs of a tristate logic are 0, 1 and indeterminant. A. Both A and R are correct and R is correct explanation of A B. Both A and R are correct but R is not correct explanation of A C. A is true, R is false D. A is false, R is true

Assertion (A): Two transistors one n-p-n and the other p-n-p are identical in all respects (doping, construction, shape, size). The n-p-n transistor will have better frequency response. Reason (R): The electron mobility is higher than hole mobility. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): Typical value of thermal resistance from source to sink of an SCR is about 0.3° C/W Reason (R): Heat sinks of thyristors are generally made of aluminium. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): When Diode used as rectifier the reverse breakdown voltage should not be exceeded. Reason (R): A high inverse voltage can destroy a p-n junction. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): When VDS is more than rated value the drain current in a JFET is very high. Reason (R): When VDS is more than rated value, avalanche breakdown occurs. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): When a high reverse voltage is applied to a p-n junction the diode breaks down. Reason (R): High reverse voltage causes Avalanche effect. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): When a photoconductive device is exposed to light, its bulk resistance increases. Reason (R): When exposed to light, electron hole pairs are generated in the photoconductive device. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

D When exposed to light bulk resistance decreases. Therefore, A is wrong.

C Junction temperature is about 120°C. Hence R is wrong.

Assertion (A): When an SCR is conducting, the voltage drop across is about 1 V. Reason (R): When an SCR is conducting, the junction temperature is about 200°C. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assertion (A): When reverse voltage across a p-n junction is increased, the junction capacitance decreases. Reason (R): Capacitance of any layer is inversely proportional to thickness. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): When the anode current of an SCR starts increasing during turn on process, the anode cathode voltage drop starts decreasing. Reason (R): During turn on the reverse biased junction in SCR breaksdown. A. Both A and R are correct and R is correct explanation of A B. Both A and R correct but R is not correct explanation of A C. A is correct but R is wrong D. A is wrong but R is correct

Assume that a particular IC has a supply voltage (Vcc) equal to +5 V and ICCH = 10 mA and ICCL = 23 mA. What is the power dissipation for the chip? A. 50 mW B. 82.5 mW C. 115 mW D. 165 mW

Assume that in a certain 4-bit weighted ladder DAC, the input representing the most significant bit is applied to a 20 k resistor. What is the size of the resistor that represents the least significant bit? A. 2.5 k B. 5 k C. 80 k D. 160 k

C At 0 K a semiconductor is perfect insulator. At room temperature it is slightly conducting.

At room temperature a semiconductor material is A. perfect insulator B. conductor C. slightly conducting D. any of the above

At room temperature kT = 0.03 eV. A. True B. False

At room temperature the current in an intrinsic semiconductor is due to A. holes B. electrons C. ions D. holes and electrons

B Covalent bonds are broken.

At very high temperatures the extrinsic semi conductors become intrinsic because A. drive in diffusion of dopants and carriers B. band to band transition dominants over impurity ionization C. impurity ionization dominants over band to band transition D. band to band transition is balanced by impurity ionization

At what kind of operating frequency diffusion or transition is a capacitor represented in parallel with the ideal diode? A. low frequency B. moderate frequency C. mid frequency D. very high frequency

At what region of operation is the base-emitter junction forward biased and the base-collector junction reverse biased? A. saturation B. linear or active C. cutoff D. none of the above

At which of the following condition(s) is the depletion region uniform? A. No bias B. VDS > 0 V C. VDS = VP D. None of the above

At which of the following condition(s) is the depletion region uniformed? A. no bias B. VDS > 0 V C. VDS = VP D. none of the above

At which of the following is the level of VDS equal to the pinch-off voltage? A. When ID becomes equal to IDSS B. When VGS is zero volts C. IG is zero D. All of the above

At which of the following is the level of VDS equal to the pinch-off voltage? A. when ID becomes equal to IDSS B. when VGS is zero volts C. IG is zero D. all of the above

A JFET operates in ohmic region when A. VGS = 0 B. VGS is less than pinch off voltage C. VGS = is Positive D. VGS = VDS

Addition of a small amount of antimony to germanium will result in A. formation of P-type semiconductor B. more free electrons than holes in the semiconductor C. antimony concentrating on the edges of the crystals D. increased resistance

Assertion (A): Field emission is substantially independent of temperature. Reason (R): When a high electric field is created at metal surface field emission may occur. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Consider the following circuit configuration 1 common Emitter 2 common Base 3 emitter follower 4 emitter follower using Darlington pair. The correct sequence in increasing order of I/P impedance of these configuration: A. 2, 1, 4, 3 B. 1, 2, 4, 3 C. 2, 1, 3, 4 D. 1, 2, 3, 4

Eg is the band gap, A is pre-factor, k is Boltzmann constant? Which one of the following is the remaining grade of paper used in paper capacitor, besides the other two grade of paper-low and extra low loss? A. Strong dielectric B. Regular C. Rough D. High loss

In a photo transistor the photocurrent is A. emitter base junction B. collector base junction C. collector D. either (a) or (b)

In a triode the potential of grid (with respect to cathode) is usually A. zero B. negative C. positive D. zero or positive

In photoelectric emission the maximum kinetic energy of emitted electron is proportional to A. SQRT f B. f C. f^2 D. f^3

The rating of a transformer to deliver 100 watts of D.C. power to a load under half wave rectifier will be nearly A. 1 kVA B. 350 VA C. 175 VA D. 108 VA

The ratio of diffusion constant for hole DP to the mobility for holes is proportional to A. T^2 B. T C. 1/T D. T^3

Which of the following is known as insulated gate FET? A. JFET B. MOSFET C. Both JFET and MOSFET D. None of the above

C 1000 equals decimal 8 Therefore all segments will lit up.

BCD input 1000 is fed to a 7 segment display through a BCD to 7 segment decoder/driver. The segments which will lit up are A. a, b, d B. a, b, c C. all D. a, b, g, c, d

Because microprocessor CPUs do not understand mnemonics as they are, they have to be converted to ________. A. hexadecimal machine code B. binary machine code C. assembly language D. all of the above

Between which points does UJT exhibit negative resistance characteristics A. between peak and valley points B. before peak point C. after peak point D. after valley point

Binary number 11001 is equivalent to decimal number A. 35 B. 15 C. 105 D. 25

Both OR and AND gates can have only two inputs. A. True B. False

A P-N junction offers A. high resistance in forward as well as reverse direction B. low resistance in forward as well as reverse direction C. conducts in forward direction only D. conducts in reverse direction only

An insulator will conduct when the A. voltage applied is more than the breakdown voltage B. temperature is raised to very high level C. either (a) or (b) above D. none of the above

Consider the following statements. 1 Etching 2 Exposure to UV radiation 3 Stripping 4 Developing After a wafer has been coated with photo resist the correct sequence of these steps in photolithography is A. 2, 4, 3, 1 B. 2, 4, 1, 3 C. 4, 2, 1, 3 D. 3, 2, 3, 1

In CE connection, the leakage current of a transistor is about A. 10 x 10-9 A B. 5 x 10-6 A C. 200 x 10-6 A D. 5 x 10-3 A

In a common emitter BJT amplifier, the maximum usable supply voltage is limited by A. avalanche Beakdown of Base-Emitter junction B. collector emitter breakdown voltage with base open(βVCEO) C. collector emitter breakdown voltage with emitter open(βVCEO) D. zener break down voltage of the emitter base junction

In a p-n-p transistor operating in forward active mode A. base is positive with respect to emitter and collector B. base is negative with respect to emitter and collector C. emitter is positive with respect to base and base is positive with respect to collector D. emitter is negative with respect to base and base is positive with respect to collector

In an integrated circuit the SiO2 layers provide A. electrical connection to external Ckt. B. physical strength C. isolation D. conducting path

In modern MOSFETS, the material used for the gate is A. high purity silicon B. high purity silica C. heavily doped polycrystalline silicon D. epitaxial grown silicon

The early effect in a BJT is caused by A. fast turn on B. fast turn off C. large collector base reverse bias D. large emitter base forward bias

The maximum power handling capacity of a resistor depends on A. total surface area B. resistance value C. thermal capacity of the resistor D. resistivity of the material used in the resistor

The output v-i characteristics of enhancement type MOSFET has A. only an ohmic region B. only a saturation region C. an ohmic region at low voltage value and a saturation region at high voltage D. a saturation region at low voltage value and an ohmic region at high voltage

Calculate ID if RD = 30 and VD = 0.84 V. A. 28 mA B. 0.028 mA C. 2.8 A D. 280 µA

Calculate minority current ICO if IC = 20.002 mA and IC majority = 20 mA. A. 20 A B. 0.002 A C. 2 nA D. 2 A

Calculate static resistance RD of a diode having ID = 30 mA and VD = 0.75 V. A. 25Ω B. 40Ω C. 0.04Ω D. 0.025Ω

Calculate the power dissipation of a diode having ID = 40 mA. A. 28 mW B. 28 W C. 280 mW D. undefined

Calculate the temperature coefficient in %/º C of a 10-V nominal Zener diode at 25º C if the nominal voltage is 10.2 V at 100º C. A. 0.0238 B. 0.0251 C. 0.0267 D. 0.0321

Can a 74HCMOS logic gate directly connect to a 74ALSTTL gate? A. Yes B. No

Class A and class B chopper A. operate in first quadrant B. operate in second quadrant C. class A chopper operates in first quadrant while class B operates in second quadrant D. may operate in either first or second quadrant

B No, gates are used for edge triggering

Computers use RC circuit for edge triggering. A. True B. False

Consider the following statements : A clamper circuit 1 adds or subtracts a dc voltage to a waveform 2 does not change the waveform 3 amplifiers the waveform Which are correct? A. 1, 2 B. 1, 3 C. 1, 2, 3 D. 2, 3

D Oxide layer cannot have any effect on melting point of silicon. Moreover before melting silicon breaks down.

Consider the following statements: The function of oxide layer in an IC device is to 1. mask against diffusion or non implant 2. insulate the surface electrically 3. increase the melting point of silicon 4. produce a chemically stable protective layer Of these statements: A. 1, 2, 3 are correct B. 1, 3, 4 are correct C. 2, 3, 4 are correct D. 1, 2, 4 are correct

Contiguous sequences of bytes or words are called ________. A. data transfer B. arithmetic C. loops and jumps D. strings

Crossover distortion behaviour is characteristic of A. class A O/P stage B. class B O/P stage C. class AB output stage D. common pulse O/P state

Current chopping leads to A. over voltage B. over current C. both over voltage and over current D. either over voltage or over current

B Since current does not divide equally, current derating is necessary.

Current derating may be necessary when thyristors are operating in A. series B. parallel C. series or parallel D. none of the above

Consider the following statement: At finite temperature, magnetic dipoles in a material are randomly oriented giving low magnetization. When magnetic field H is applied, the magnetization? 1 Increases with H 2 Decreases with H 3 Decreases with temp for constant H Which of the statement given above is/are correct? A. 1 B. 2 C. 2, 3 D. 1 and 3

Epitaxial growth is used in ICs A. because it produces low parasitic capacitance B. because it yields back to back isolating pn Junction C. to grow single crystal n doped silicon on a single crystal P-type substrate D. to grow Selectivity single crystal P doped silicon of one resistivity on a P type substrate of a different resistivity

The temperature of cathode is increased from 2500K to 2600K. The increase in thermionic emission current is about A. 0.1% B. 4% C. 50% D. 150%

Which rectifier has the best ratio of rectification? A. Half wave rectifier B. Full wave rectifier C. Bridge rectifier D. Three phase full wave rectifier

A Due to drift.

DC amplifiers have a tendency to be unstable. A. True B. False

DMA is particularly suited for data transfer between the ________. A. disk drive and CPU B. disk drive and RAM C. disk drive and ROM D. disk drive and I/O

DeMorgan's first theorem shows the equivalence of A. OR gate and Exclusive OR gate B. NOR gate and Bubbled AND gate C. NOR gate and NAND gate D. NAND gate and NOT gate

Decimal 43 in hexadecimal and BCD number system is respectively. A. B2, 01000011 B. 2B, 01000011 C. 2B, 00110100 D. B2, 01000100

Decimal number 10 is equal to binary number A. 1110 B. 1010 C. 1001 D. 1000

Decimal number 46 in excess 3 code = A. 1000 1001 B. 0111 1001 C. 0111 1111 D. 1000 1111

Define a race condition for a flip-flop. A. The inputs to a trigger device are changing slightly before the active trigger edge. B. The inputs to a trigger device are changing slightly after the active trigger edge. C. The inputs to a trigger device are changing at the same time as the active trigger edge.

Determine ICQ at a temperature of 175ºC if ICQ = 2 mA at 25ºC for RB /RE = 20 due to the S(β) stability factor. A. 2.417 mA B. 2.392 mA C. 2.25 mA D. 2.58 mA

Determine odd parity for each of the following data words: 1011101 11110111 1001101 A. P = 1, P = 1, P = 0 B. P = 0, P = 0, P = 0 C. P = 1, P = 1, P = 1 D. P = 0, P = 0, P = 1

Determine the change in IC from 25ºC to 175ºC for the transistor defined in the table for fixed-bias with RB = 240 k and β = 100 due to the S(VBE) stability factor. A. 145.8 μA B. 145.8 nA C. -145.8 μA D. -145.8 nA

Determine the nominal voltage for the Zener diode at a temperature of 120º C if the nominal voltage is 5.1 volts at 25º C and the temperature coefficient is 0.05%/º C. A. 4.6 V B. 4.86 V C. 5.1 V D. 5.34 V

Determine the peak for both half cycles of the output waveform if V polarity is changed in Figure 2.85. A. 16 V, -4 V B. 16 V, 4 V C. -16 V, 4 V D. -16 V, -4 V

Determine the peak value of the output waveform if the polarity of 5 V is changed in Figure 2.76. A. 25 V B. 15 V C. -25 V D. -15 V

Determine the total discharge time for the capacitor in a clamper having C = 0.01 F and R = 500 k. A. 5 ms B. 25 ms C. 2.5 ms D. 50 ms

Determining rd to a high degree of accuracy from a characteristic curve is very accurate. A. True B. False

Dielectric strength of polythene is around A. 10 kV/mm B. 40 kV/mm C. 100 kV/mm D. 140 kV/mm

Diodes are connected _____ to increase the current-carrying capacity. A. in series B. in parallel C. in parallel-series D. none of the above

B It is near conduction band.

Donor energy level is n type semiconductor is very near valence band. A. True B. False

During a memory read operation, the CPU fetches ________. A. a program instruction B. an address C. data D. all of the above

During a read operation the CPU fetches ________. A. a program instruction B. another address C. data itself D. all of the above

During forward blocking state of SCR, the voltage and current respectively are A. high and high B. low and low C. high and low D. low and high

B High speed is obtained because saturation state is avoided.

ECL has high switching speed because the transistors are A. switching between cutoff and saturation regions B. switching between cutoff and active regions C. switching between active and saturation regions D. none of the above

A This is called field emission.

Electrons can be emitted from a metal surface due to high electric field. A. True B. False

B FET amplifier is easier to analyse since gate current is negligible.

FET amplifier is more difficult to analyse than BJT amplifier. A. True B. False

FF16 when converted to 8421BCD = A. 0000 0101 0101 B. 0010 0101 0101 C. 1111 0101 0101 D. 1000 0101 0101

Fan-out for a typical TTL gate is ________. A. 100 B. 54 C. 10 D. 4

B Feedback factor is much less than 1.

Feedback factor may be less or more than 1. A. True B. False

C These magnetic materials having very low loss of current and used in high frequency circuit.

Ferrite have A. low copper loss B. low eddy current loss C. low resistivity D. higher specific gravity compared to iron

Find the FSV (full scale voltage) in a 6 bit R-2R ladder D/A converter has a reference voltage of 6.5 V. A. 6.4 V B. 0.1 V C. 7 V D. 8 V

B 350 - 2.5 (60 - 25) ∼ 250 mW.

For BJT transistor. The maximum power dissipation is specified as 350 mW if ambient temperature is 25°C. If ambient temperature is 60°C the maximum power dissipation should be limited to about A. 100 mW B. 250 mW C. 450 mW D. 600 mW

C 30° phase difference is necessary.

For a 12 pulse operation, the two 6 pulse units are fed by A. Y - Y and Y - Y transformers B. Δ - Δ and Δ - Δ transformers C. Y - Y and Y - Δ transformers D. Y - Δ and Y - Δ transformers

For a 4-bit DAC, the least significant bit (LSB) is ________. A. 6.25% of full scale B. 0.625% of full scale C. 12% of full scale D. 1.2% of full scale

For a CMOS gate, which is the best speed-power product? A. 1.4 pJ B. 1.6 pJ C. 2.4 pJ D. 3.3 pJ

For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in illumination results in A. a change in O.C. voltage B. a change in S.C. current C. a decrease in resistance D. an increase in resistance

For a photoengraving the mask used is A. master mask B. slave mask C. working mask D. photo mask

For an "on" transistor, the voltage VBE should be in the neighborhood of 0.7 V. A. True B. False

For an illumination control circuit it is advisable to use a matched TRIAC-DIAC pair. A. True B. False

A VT depends upon MOSFET construction, hence it will Independent from MOSFET parameters.

For an n-channel enhancement type MOSFET, if the source is connected at a higher potential than that of the bulk (VSB > 0), the threshold voltage VT of the MOSFET will A. remain unchanged B. decrease C. change Polarity D. increase

D dc remains confined within BJT. Only ac signal comes out.

For dc the current through coupling capacitor in CE amplifier circuit is A. very high B. high C. low D. zero

For high frequencies a capacitor like A. an open circuit B. a short circuit C. either open circuit or short circuit D. none of the above

For the BJT to operate in the active (linear) region, the base-emitter junction must be _____-biased and the base-collector junction must be _____-biased. A. forward, forward B. forward, reverse C. reverse, reverse D. reverse, forward

For the BJT to operate in the saturation region, the base-emitter junction must be _____-biased and the base-collector junction must be _____-biased. A. forward, forward B. forward, reverse C. reverse, reverse D. reverse, forward

For the K map in the given figure the simplified Boolean expression is A. ¬A¬C + ¬A¬D + ABC B. ¬AC + ¬A¬D + ABC C. ¬AC + ¬A¬D + ACD D. ¬A¬C + ¬A¬D + AB¬C

For the gate in the given figure the output will be A. 0 B. 1 C. A D. ¬A

For the minterm designation Y = ∑ m (1, 3, 5, 7) the complete expression is A. Y = ¬A¬BC + A¬BC B. Y = ¬A¬BC + A¬BC + ABC + ¬ABC C. Y = ¬A¬B¬C + ¬A¬BC + ¬ABC + A¬BC D. Y = ¬A¬B¬C + ABC + ¬A¬BC + A¬BC

For the truth table of the given figure Y = A. A + B + C B. ¬A + BC C. ¬A D. ¬B

For the typical transistor amplifier in the active region, VCE is usually about _____ % to _____ % of VCC. A. 10, 60 B. 25, 75 C. 40, 90

For what kind of amplifications can the active region of the common-emitter configuration be used? A. Voltage B. Current C. Power D. All of the above

For what kind of amplifications can the active region of the common-emitter configuration be used? A. voltage B. current C. power D. all of the above

Forward DV/DT rating of an SCR is A. the maximum rate of rise of anode voltage which will trigger the SCR B. the maximum rate of rise of anode voltage which will not trigger the SCR if gate signal is applied C. the maximum rate of rise of anode voltage which will not trigger the SCR if gate signal is not applied D. either (b) or (c)

From which instant is the turn off time of a thyristor defined A. when anode voltage becomes zero B. when anode current becomes zero C. when both anode voltage and current become zero D. none of the above

B GaAs has very large band gap and high carrier mobility.

GaAs has an energy gap 1.43 eV the optical cut off wavelength of GaAs would lie in the A. visible region of the spectrum B. infrared region of the spectrum C. ultraviolet region of the spectrum D. for ultraviolet region of the spectrum

Ge and Si have a(n) _____ coefficient in forward bias. A. positive temperature B. negative temperature C. absolute temperature D. temperature free

Generally the gain of a transistor amplifier falls at high frequencies due to the A. internal capacitance of device B. coupling capacitor at the I/P C. skin effect D. coupling capacitor at the O/P

Generally the value of ac resistance is _____ the value of dc resistance at the same operating point. A. smaller than B. larger than C. the same as D. unrelated to

Generally, the gain of a transistor amplifier falls at high frequency due to the A. internal capacitance of the device B. coupling capacitor at the I/P C. skin effect D. coupling capacitor at the O/P

Generally, the voltage measured at an unused TTL input would typically be measured between: A. 1.4 to 1.8 V. B. 0 to 5 V. C. 0 to 1.8 V. D. 0.8 to 5 V.

HVDC systems are preferable for only long distances. A. True B. False

A To reduce ripple, 12 pulse converters are used in HVDC.

HVDC transmission systems generally use A. 12 pulse converters B. 6 pulse converters C. 3 pulse converters D. either 12 or 6 pulse converters

Half bridge and full bridge inverters of one type use different commutation methods. A. True B. False

Hand-held instruments are available to measure _____ for the BJT. A. βdc B. IDSS C. VP D. all of the above

Hand-held instruments are available to measure ________ for the BJT. A. Bdc B. IDSS C. VP D. All of the above

B Surface area of heat dissipating surface increases. Therefore heat dissipation is faster.

Heat sink results in A. slower dissipation of heat to atmosphere B. faster dissipation of heat to atmosphere C. lower ambient temperature D. lower transistor power

Hexadecimal number E is equal to binary number A. 1110 B. 1101 C. 1001 D. 1111

How are unwanted frequencies removed prior to digital conversion? A. Pre-filters B. Digital signal processing C. Sample-and-hold circuits D. All of the above

How can ECL have both a NOR and an OR output? A. ECL does not have this feature. B. They are simply the inverse of each other.

How does the 4000 series of CMOS logic compare in terms of speed and power dissipation to the standard family of TTL logic? A. more power dissipation and slower speed B. more power dissipation and faster speed C. less power dissipation and faster speed D. less power dissipation and slower speed

How is odd parity generated differently from even parity? A. The first output is inverted. B. The last output is inverted

How is the speed-power product of a logic family determined? A. The propagation delay in s is multiplied by the power dissipation in mW. B. The propagation delay in ms is multiplied by the power dissipation in W. C. The propagation delay in ns is multiplied by the power dissipation in mW. D. The propagation delay in ns is multiplied by the power dissipation in W.

How many 74LSTTL logic gates can be driven from a 74TTL gate? A. 10 B. 20 C. 200 D. 400

How many bits are used in the data bus? A. 7 B. 8 C. 9 D. 16

How many buses are connected as part of the 8085A microprocessor? A. 2 B. 3 C. 5 D. 8

How many carrier(s) participate(s) in the injection process of a unipolar device? A. 1 B. 2 C. 0 D. 3

How many individual pnp silicon transistors can be housed in a 14-pin plastic dual-in-line package? A. 4 B. 7 C. 10 D. 14

How many layers of material does a transistor have? A. 1 B. 2 C. 3 D. 4

How many orbiting electrons does the germanium atom have? A. 4 B. 14 C. 32 D. 41

How many terminals can a MOSFET have? A. 2 B. 3 C. 4 D. 3 or 4

How many terminals does a diode have? A. 1 B. 2 C. 3 D. 4

How many valence electrons does a silicon atom have? A. 1 B. 2 C. 3 D. 4

How much is the base-to-emitter voltage of a transistor in the "on" state? A. 0 V B. 0.7 V C. 0.7 mV D. undefined

How much setup time (ts) is required for the 74LS76? A. 5 ns B. 10 ns C. 20 ns D. 40 ns

I/O mapped systems identify their input/output devices by giving them a(n) ________. A. 8-bit port number B. 16-bit port number C. 8-bit buffer number D. 8-bit instruction

If 4 quadrant operation is required we need A. dual converter B. full converter C. semi converter D. none of the above

If ICCH is specified as 1.1 mA when VCC is 5 V and if the gate is in a static (noncharging) HIGH output state, the power dissipation (PD) of the gate is ________. A. 5.5 mW B. 5.5 W C. 5 mW D. 1.1 mW

If Vcc of a 555 timer circuit is set to +10 V what is the level of output voltage from the circuit? A. VOH = 10 V, VOL = 0 V B. VOH = 10 V, VOL = 0.1 V C. VOH = 8.5 V, VOL = 0 V D. VOH = 8.5 V, VOL = 0.1 V

If Vdc1 is the dc output voltage in half wave controlled rectifier circuit feeding resistive load and Vdc2 is the dc output voltage in full wave controlled rectifier circuit (M - 2 connection) feeding resistive load, then A. Vdc1 = 0.5 Vdc2 for all values of firing angle B. Vdc1 = Vdc2 for all values of firing angle C. Vdc1 ≤ 0.5 Vdc2 for all values of firing angle D. Vdc1 ≥ 0.5 Vdc2 for all values of firing angle

If a DAC has a full-scale, or maximum, output of 12 V and accuracy of 0.1%, then the maximum error for any output voltage is ________. A. 12 V B. 120 mV C. 12 mV D. 0 V

D Since the majority of charge carrier is better in Ge than in Si, for the same concentration of charge carriers, the conductivity of Ge is higher than that of Si.

If a sample of germanium and a sample of Si have the impurity density and are kept at room temperature then A. both will have equal value of resistivity B. both will have equal -ve resistivity C. resistivity of germanium will be higher than that of silicon D. resistivity of Si will be higher than of germanium

If all inputs to a TTL NAND gate are low, what is the ON, OFF condition of each transistor in the circuit? A. Q1-ON, Q2-OFF, Q3-ON, Q4-OFF B. Q1-ON, Q2-ON, Q3-OFF, Q4-OFF C. Q1-OFF, Q2-OFF, Q3-ON, Q4-ON D. Q1-OFF, Q2-ON, Q3-OFF, Q4-ON

If all the LEDs in a seven segment display are turned on, the number displayed is A. 1 B. 3 C. 0 D. 8

If for a silicon n-p-n transistor, the base to emitter voltage (VBE) is 0.7 V and the collector to base voltage VCB is 0.2 Volt, then the transistor is operating in the A. normal active mode B. saturation mode C. inverse active mode D. cut off mode

(1024 x 8)/(256 x 1 ) = 32.

If memory chip size is 256 x 1 bits, the number of chips required to make 1 k byte memory is A. 8 B. 12 C. 24 D. 32

If the Q of a single stage single tuned amplifier is doubled, the bandwidth will A. remain the same B. become half C. become double D. become four times

If the frequency is less than the damped frequency in a series- inverter A. the distortion of output voltage waveform is low B. the distortion of output voltage waveform is high C. the distortion of output voltage may be high or low depending on the load impedance D. none of the above

If the functions w, x, y, z are as follows. Then A. w = z, x = z B. w = z, x = y C. w = y D. w = y = z

If the ladder reference voltage is 2 V, then minimum comparator resolution required is A. 0.125 V B. 1.25 V C. 12.5 V D. 0

If the positive lead of an ohmmeter is connected to the base and the negative lead to the emitter, a low resistance reading would indicate a ________ transistor and a high resistance reading would indicate a ________ transistor. A. npn, pnp B. pnp, npn C. npn, npn D. pnp, pnp

If the resistor in the Schmitt trigger astable multivibrator is a variable resistor, what part of the output voltage waveform will change when the resistance is changed? A. the shape of the waveform B. the amplitude of the waveform C. the period of the waveform D. none of the above

C Increase of reverse voltage widens the depletion layer and junction capacitance decreases. However the decrease in capacitance is not proportional to increase in voltage.

If the reverse voltage across a p-n junction is increased three times, the junction capacitance A. will decrease B. will increase C. will decrease by an approximate factor of about 2 D. will increase by an approximate factor of about 2

If the secondary voltage of the transformer in Figure 2.124 is 5 V, what is the voltage measured from the negative terminal of C4 to the negative terminal of the transformer? A. -10 V B. -20 V C. 10 V D. 20 V

C Turn on time is less than 3 μs while turn off time is between 10-300 μs.

If ton and toff are the turn on and turn off times of a thyristor, then A. ton and toff are almost equal B. ton >> toff C. toff >> ton D. ton is about twice toff

If we connect two silicon unilateral switches in anti- parallel we get A. SCR B. SBS C. SCS D. UJT

In 180° mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time. A. True B. False

In 2's complement representation the number 11100101 represents the decimal number A. +37 B. -31 C. +27 D. -27

In Class C operation the collector current looks like A. full sine wave B. half sine wave C. narrow pulses D. nearly half sine wave

In Jone chopper, the commutating element A. is a capacitor B. is a capacitor and an inductor C. is a capacitor and an auto transformer D. none of the above

In a 3 input NAND gate, the number of states in which output is 1 equals A. 8 B. 1 C. 6 D. 5

In a 3 phase bridge inverter with 120° mode of operation the. number of thyristors conducting at one time are A. 1 B. 2 C. 3 D. 4

In a 3 phase bridge inverter, the gating signals for the three phases have a phase difference of A. 120° B. 60° C. 240° D. any of the above

In a 3 phase full converter feeding a highly inductive load, the average load current is 150 A. The peak current through thyristor is A. 150 A B. 75 A C. 50 A D. 300 A

C Each thyristor conducts for one-third of one cycle.

In a 3 phase full converter the average load current is 150 A. The average thyristor current is A. 150 A B. 75A C. 50 A D. 25 A

In a 3 phase full converter, the instantaneous output voltage can have negative part if A. firing angle is less than 60° B. firing angle is less than 90° C. firing angle is more than 60° D. firing angle is more than 90°

D In a three-phase full wave regulator, output voltage is zero if a ≥ 150°.

In a 3 phase full wave regulator feeding a star connected resistance load the input voltage is 400 V line to line. The firing angle is 160°. The line to line output voltage would be A. 400 V B. about 100 V C. about 20 V D. zero

In a 3 phase full wave regulator feeding a star connected resistance load, firing angle is 75°. Then the number of thyristors conducting at one time is A. 1 B. 2 C. 3 D. 4

B Since output voltage is zero if a ≥ 150°, the possible range of firing angles is 0 ≤ a ≤ 150°.

In a 3 phase full wave regulator feeding resistance load connected in star, the possible range of firing angle a is A. 0 ≤ a ≤ 180° B. 0 ≤ a ≤ 150° C. 0 ≤ a ≤ 120° D. 0 ≤ a ≤ 90°

B It is a 6 pulse converter.

In a 3 phase fully controlled converter the firing frequency is A. 3 times the line frequency B. 6 times the line frequency C. 9 times the line frequency D. 12 times the line frequency

C Vdc ∝ (1 + cos a). Maximum possible output voltage occurs when a = 0.

In a 3 phase semiconverter, the dc output voltage for a certain firing angle is 50% of the maximum possible value. The firing angle is A. 30° B. 60° C. 90° D. 120°

B Since the circuit has 3 thyristors, firing frequency is three times the line frequency.

In a 3 phase semiconverter, the firing frequency is A. equal to line frequency B. 3 times the line frequency C. 6 times the line frequency D. 12 times the line frequency

In a 3 phase semiconverter, the freewheeling diode comes into operation only if firing angle A. is zero B. is 60° C. is more than 60° D. is more than 90°

In a 3 phase semiconverter, the output voltage becomes discontinuous for A. firing angle > 30° B. firing angle > 60° C. firing angle > 90° D. firing angle > 120°

In a 4-bit R/2R ladder digital-to-analog converter, because of negative feedback, the operational amplifier keeps the inverting (minus) input near ________. A. 5 volts B. zero volts C. a voltage determined by the binary weighted input D. none of the above

In a 7 segment LED display, the minimum number of segments is activated when the input decimal number is A. 0 B. 1 C. 2 D. 3

In a 7 segment display, LEDs b and c lit up. The decimal number displayed is A. 9 B. 7 C. 3 D. 1

A Minimum number of outputs when input is decimal 1 and maximum number of outputs when input is decimal 8.

In a BCD to 7 segment decoder the minimum and maximum number of outputs active at any time is A. 2 and 7 B. 3 and 7 C. 1 and 6 D. 3 and 6

D All voltages and currents have reverse polarity.

In a BJT circuit a pnp transistor is replaced by npn transistor. To analyse the new circuit A. all calculations done earlier have to be repeated B. replace all calculated voltages by reverse values C. replace all calculated currents by reverse values D. replace all calculated voltages and currents by reverse values

B Since ac collector resistance is less than dc collector resistance, slope of ac load line is more than that of dc load line.

In a CE amplifier A. both ac and dc load lines have the same slope B. the ac load line has more slope than dc load line C. the ac load line has less slope than dc load line D. the two load lines may have slope more than the other

C Common emitter means emitter at ground potential.

In a CE amplifier circuit the ac voltage between emitter and ground A. is very high B. may be high or low C. is zero D. depends on circuit configuration

B Since dc is flowing through emitter resistance, dc voltage cannot be zero.

In a CE amplifier circuit the dc voltage between emitter and ground A. is always zero B. cannot be zero C. may or may not be zero D. is negative

A Low load resistance means high current and hence over loading.

In a CE amplifier drives a low load resistance directly the result will be A. overloading of amplifier B. underloading of amplifier C. overloading or underloading of amplifier depending on circuit D. none of the above

In a CE amplifier the ac emitter resistance A. is zero B. is high C. is very high D. may have any value

D Since the output is taken across collector resistance, short-circuiting collector resistance will decrease output voltage.

In a CE amplifier the collector resistance is short circuited. The ac output voltage will A. increases B. remains the same C. increases or decreases D. decreases

C When ac collector resistance is very high, the net resistance is the same as dc collector resistance

In a CE amplifier the dc load line is the same as ac load line when A. ac collector resistance and dc collector resistance are equal B. ac collector resistance and dc emitter resistance are equal C. ac collector resistance is very high D. ac collector resistance is one half of dc collector resistance

A Input is applied to base with emitter grounded. The input impedance is the ratio of ac base voltage to ac base current.

In a CE amplifier the input impedance is equal to the ratio of A. ac base voltage to ac base current B. ac base voltage to ac emitter current C. ac emitter voltage to ac collector current D. ac collector voltage to ac collector current

A Since output is taken from collector terminal, output voltage is equal to collector current multiplied by collector resistance.

In a CE amplifier, the output voltage is equal to product of A. ac collector current and ac collector resistance B. ac base current and ac collector resistance C. ac emitter current and ac emitter resistance D. ac collector current and source resistance

In a D latch A. data bit D is fed to S input and D^ to R input B. data bit D is fed to R input and D^ to S input C. data bit D is fed to both R and S inputs D. data bit D^ is not fed to any input

In a DIP the spacing between pins is typically ________. A. 5 mils B. 10 mils C. 50 mils D. 100 mils

In a JFET A. drain current is very nearly equal to source current B. drain current is much less than source current C. drain current may be equal to or less than source current D. drain current may be even more than source current

In a JK master slave flip flop A. master is clocked when clock is low B. slave is clocked when clock is high C. master is clocked when clock is high and slave is clocked when clock is low D. master is clocked when clock is low and slave is clocked when clock is high

In a TTL circuit, if an excessive number of load gate inputs are connected, ________. A. VOH(min) drops below VOH B. VOH drops below VOH(min) C. VOH exceeds VOH(min) D. VOH and VOH(min) are unaffected

In a bipolar junction transistor the base region is made very thin so that A. recombination in base region is minimum B. electric field gradient in base is high C. base can be easily fabricated D. base can be easily biased

A Base is very thin and therefore recombination is minimum in both p-n-p and n-p-n transistors.

In a bipolar transistor A. recombination in base regions of both n-p-n and p-n-p transistor is low B. recombination in base regions of both n-p-n and p-n-p transistors is high C. recombination in base region of n-p-n transistor is low but that in p-n-p transistor is high D. recombination in base region of p-n-p transistor is low but that in n-p-n transistor is high

C Since there are two p-n junctions, there are two depletion layers and 0.7 V across each layer.

In a bipolar transistor the barrier potential A. 0 B. a total of 0.7 V C. 0.7 V across each depletion layer D. 0.35 V

In a bipolar transistor which current is largest A. collector current B. base current C. emitter current D. base current or emitter current

In a bridge inverter A. an output transformer is essential B. an output transformer is not essential C. an output transformer cannot be connected D. an output transformer, if used, can improve the efficiency of the circuit

In a bridge inverter with single pulse width modulation A. the output frequency is equal to frequency of reference signal B. the output frequency is equal to frequency of control signal C. either (a) or (b) D. neither (a) nor (b)

In a bridge rectifier circuit the rms value of input ac voltage is 10 V. The PIV across each diode is A. 7.07 V B. 14.14 V C. 10 V D. 28.28 V

In a certain inverter circuit each thyristor carries 26.67 A for 60°, 13.33 A for 120° and zero A for 180° of the cycle. The rms current of thyristor is A. 20 A B. 13.33 A C. 6.67 A D. 3.33 A

C In bridge connection PIV is half of that in M-2 connection.

In a circuit using a full wave converter (M - 2 connection) the PIV of each thyristor is 400 V. For the same output voltage and fully controlled bridge converter, PIV will be A. 400 V B. 800 V C. 200 V D. 200sqrt2 V

A A good power supply does not allow output voltage to vary by more than 1% .

In a commercially available good power supply the voltage regulation is about A. 1% B. 5% C. 10% D. 20%

In a controlled rectifier a freewheeling diode is necessary if the load is A. inductive B. resistive C. capacitive D. any of the above

In a curve tracer, the ________ reveals the distance between the VGS curves for the n-channel device. A. vertical sens. B. horizontal sens. C. Per step D. gm

In a cycloconverter it is possible to vary A. only output frequency B. only output voltage C. both output voltage and frequency but not simultaneously D. both output voltage and output frequency simultaneously

B This is due to high level of doping.

In a degenerate n type semiconductor material, the Fermi level, A. is in valence band B. is in conduction band C. is at the centre in between valence and conduction bands D. is very near valence band

In a digital representation of voltages using an 8-bit binary code, how many values can be defined? A. 16 B. 64 C. 128 D. 256

In a digital reproduction of an analog curve, accuracy can be increased by ________. A. sampling the curve more often B. sampling the curve less often C. decreasing the number of bits used to represent each sampled value D. all of the above

B One operators as rectifier and the other as inverter.

In a dual converter both converters work as rectifiers. A. True B. False

In a dual converter operated in circulating current mode, the circulating current flows A. when load current is zero B. when load current is non-zero C. even when load current is zero D. none of the above

In a fixed-bias circuit, which one of the stability factors overrides the other factors? A. S(ICO) B. S(VBE) C. S(β) D. undefined

In a flash analog-to-digital converter, the output of each comparator is connected to an input of a ________. A. decoder B. priority encoder C. multiplexer D. demultiplexer

In a full bridge circuit supplying an RLC under damped circuit A. the waveshapes of output voltage and load current are square B. the waveshapes of output voltage and load current are sinusoidal C. the waveshapes of output voltage is square but the waveshape of load current is nearly sinusoidal D. none of the above

In a full bridge inverter, the waveshape of load current depends on A. relative values of load parameters R, L and C B. relative values of load parameters R and L C. relative values of load parameters L and C D. gating frequency

In a full bridge single phase inverter feeding RLC load A. one thyristor and one diode conduct simultaneously B. two thyristors conduct simultaneously C. two thyristors or two diodes conduct simultaneously D. four thyristors conduct simultaneously

In a full wave rectifier circuit using centre tapped transformer, the peak voltage across half of the secondary winding is 30 V. Then PIV is A. 30 V B. 60 V C. 15 V D. 10 V

A For resistive load output current is always proportional to output voltage.

In a fully controlled bridge converter feeding a resistive load the waveshapes of output voltage and output current A. are always similar B. can never be similar C. may be similar or dissimilar D. are similar only if a = 0

In a graphical representation of voltage versus time, ________ is displayed on the ________ axis and ________ is displayed on the ________ axis. A. time, y, voltage, x B. voltage, y, time, x

In a half bridge inverter each thyristor is gated at a frequency f. The output frequency is A. 2 f B. f C. 0.5 f D. 0.25 f

In a half bridge inverter the gate pulses of the two thyristors have a phase displacement of A. 60° B. 90° C. 120° D. 180°

In a half bridge inverter, the freewheeling diodes are needed A. even when load is resistive B. only when load is inductive C. only when load is inductive or capacitive D. for all types of load

In a modified series inverter A. the maximum output frequency is less than frequency of damped oscillations B. the output frequency can be even higher than the frequency of damped oscillations C. the output frequency cannot exceed the frequency of damped oscillations D. any of the above

In a modified series inverter with two inductors and two capacitors, the load current A. has 2 parallel paths B. has only one parallel path C. can have three parallel paths D. has four parallel paths

B They operate in a sequence.

In a multiphase chopper, all choppers operate together. A. True B. False

B Only one chopper operates at one time.

In a multiphase chopper, the different choppers operate in A. series and all simultaneously B. parallel and one at a time C. parallel and simultaneously D. either (b) or (c)

B Addition of acceptor atom brings Fermi level closer to valence band.

In a p type material the Fermi level is 0.3 eV above valence band. The concentration of acceptor atoms is increased. The new position of Fermi level is likely to be A. 0.5 eV above valence band B. 0.28 eV above valence band C. 0.1 eV above valence band D. below the valence band

In a parallel inverter A. each thyristor is turned on twice during each cycle B. each thyristor is turned on once during each cycle C. each thyristor is turned on either once or twice in each load cycle D. each thyristor may be turned on upto four times in each load cycle

In a parallel inverter A. the commutating capacitor C is across the primary of transformer and the load is across the secondary B. the commutating capacitor and load are connected across the secondary of transformer C. the commutating capacitor C and load are connected in series and the combination is across the secondary of transformer D. none of the above

In a particular problem, which mode has the highest level of IDQ? A. ideal B. approximate equivalent C. exact mode using characteristic curve D. none of the above

C Commonly material used as piezoelectric crystal is Barium Nitrate. Generally ferroelectric crystals and piezoelectric.

In a piezoelectric crystal, application of a mechanical stress would produce A. plastic deformation of the crystal B. magnetic Dipoles in the crystal C. electric polarization in the crystal D. shift in the Fermi level

In a piezoelectric crystal, applications of a mechanical stress would produce A. plastic deformation of the crystal B. magnetic dipoles in the crystal C. electrical polarization in the crystal D. shift in the Fermi level

In a positive edge triggered D flip flop A. D input is called direct set B. Preset is called direct reset C. Present and clear are called direct set and reset respectively D. D input overrides other inputs

In a positive edge triggered JK flip flop A. High J and High K produce inactive state B. Low J and High K produce inactive state C. Low J and Low K produce inactive state D. High J and Low K produce inactive state

In a power diode the reverse recovery time is the time from the instant the forward current is zero to the instant when reverse recovery current has decayed to A. 50% of peak reverse current B. 25% of peak reverse current C. 10% of peak reverse current D. zero value

In a reverse biased P-N junction, the current through the junction increases abruptly at A. zero voltage B. 1.2 V C. 0.72 V D. breakdown voltage

In a reverse biased p-n junction, the reverse bias is 4V. The junction capacitance is about A. 0.1 F B. 4 μF C. 10 nF D. 20 pF

A In a ripple counter the effect ripples through the counter.

In a ripple counter, A. whenever a flip flop sets to 1, the next higher FF toggles B. whenever a flip flop sets to 0, the next higher FF remains unchanged C. whenever a flip flop sets to 1, the next higher FF faces race condition D. whenever a flip flop sets to 0, the next higher FF faces race condition

In a self bias circuit for CE amplifier, the emitter resistance is made three times the original value. The collector current will A. remain the same B. become three times C. decrease D. become one-third

In a semi converter feeding a resistive load A. the waveshapes of output voltage and output current are exactly similar B. the waveshapes of output voltage and output current can not be similar C. the waveshapes of output voltage and output current are similar only for low values of firing angle D. the waveshapes of output voltage and output current may be similar or dissimilar

In a semi converter feeding a resistive load, A. the waveshapes of input voltage and input current are always similar B. the waveshapes of input voltage and input current can never be similar C. the waveshapes of input voltage and input current are similar only if firing angle is zero D. the waveshapes of input voltage and input current are similar only if firing angle is high

In a semi converter feeding a resistive load, the firing angle is a. Each thyristor conducts for A. p radians B. (p - a) radians C. (p + a) radians D. (p - 0.5 a) radians

In a series inverter A. the commutating elements L and C are in parallel B. the commutating elements L and C are in series with load C. the commutating L and C may be in series or parallel with the load D. none of the above

In a series inverter A. the commutating elements carry full load current B. the commutating elements carry upto 50% of load current C. the commutating elements do not carry load current D. any of the above

In a single phase converter using a centre tapped transformer and with a highly inductive load, the firing angles is a. Each thyristor conducts for a period A. pie B. a C. pie - a D. pie/2

In a single phase cycloconverter with centre tapped transformer A. all thyristors carry currents for equal duration B. the durations of currents in all thyristors may or may not be equal C. the durations of currents in all thyristors cannot be equal D. the duration of currents in all thyristors must be equal for satisfactory operation

In a single phase full converter fed by a source having inductance, the number of thyristors conducting during overlap is A. 1 B. 2 C. 3 D. 4

In a single phase full wave ac regulator feeding R-L load, the gate pulses A. are always of short duration B. may be of short duration C. should be rectangular with width (p - a) D. cannot be rectangular with width (p - a)

In a single phase full wave ac regulator the firing angles during both half cycles are equal. A. True B. False

B Each thyristor conducts for 50% of time.

In a single phase full wave ac regulator the rms value of load current is 20 A load is purely resistive. Then A. average thyristor current will be less than 20 A but rms thyristor current will be more than 20 A B. both the average and rms thyristor currents will be less than 20 A C. both the average and rms thyristor currents will be more than 20 A D. rms thyristor current will be 20 A and average thyristor current will be 10 A

In a single phase full wave ac regulator using two thyristors only, the gate circuits of the two thyristors A. must be isolated B. may or may not be isolated C. should be preferably, isolated D. should not be isolated

In a single phase full wave ac regulator, the firing angles in the two half cycles A. are always equal B. are sometimes equal C. are never equal D. may be equal or unequal

In a single phase full wave controlled rectifier using centre tap transformer, the voltage across each half of secondary is Vm sin ωt. The peak inverse voltage is A. 2 Vm B. Vm C. 0.5 Vm D. 0.25 Vm

B Since conduction is from a to pie + a, period of conduction is pie in each half cycle.

In a single phase full wave converter (M - 2 connection) feeding a highly inductive load, the firing angle for each thyristor is a in the respective half cycle. The period of conduction of each thyristor is A. pie - alpha B. pie C. pie + alpha D. pie - 2alpha

In a single phase full wave regulator feeding R-L load, short gate pulse are not suitable. A. True B. False

A Range of control of a is 0 ≤ a ≤ pie.

In a single phase full wave regulator feeding R-L load, the minimum firing angle can be zero. A. True B. False

In a single phase full wave regulator feeding a resistive load, the average current over one full cycle A. is always zero B. cannot be zero C. may be sometimes zero D. is always positive

In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally A. equal B. different C. equal or different D. different but sometimes equal

In a single phase half wave ac regulator feeding a resistive load, the rms load current A. is always positive B. may be positive or negative C. is always negative D. can be even zero

In a single phase half wave converter feeding resistive load and full wave converter (M - 2 connection) feeding a resistive load the circuit conditions are similar. The firing angle is a. Then the waveshapes of voltages across thyristors A. are similar B. are not similar C. may be similar or dissimilar D. are similar only for some values of a

In a single phase semi-converter the number of thyristors is A. 16 B. 8 C. 4 D. 2

In a step down chopper using pulse width modulation, Ton = 3 x 10-3 and Toff = 1 x 10-3 s. The chopping frequency is A. 333.33 B. 250 C. 500 D. 1000

In a stud mounted SCR, the stud is A. in thermal contact with heat sink B. insulated from heat sink C. in electrical and thermal contact with heat sink D. in either electrical or thermal contact with heat sink

In a three input AND gate A = 1, B = 1, C = 0 The output Y = A. ABC B. ¬ABC C. AB¬C D. A¬BC

In a three phase series inverter, the firing frequency is A. three times output frequency B. six times output frequency C. twice the output frequency D. equal to output frequency

In a three phase to single phase full wave bridge cycloconverter, the number of thyristors is A. 36 B. 18 C. 12 D. 8

C Gate current does not affect the magnitude of anode current.

In a thyristor the gate current is increased, then A. anode current will increase B. anode current will decrease C. anode current will remain constant D. anode current may increase or decrease

In a thyristor the gate lead is connected to the n layer near the p layer to which anode is connected. A. True B. False

In a thyristor, the forward breakover voltage A. is constant B. may be constant or may depend on gate current C. decreases as gate current is increased D. increases as gate current is increased

In a thyristors are i = kv^a. The value of a is A. about 0.5 B. about 2 C. about 5 D. about 20

In a transistor CE mode, VCC = +30 V. If the transistor is in cut off region, VCE = A. +30 V B. +20 V C. 10 V D. zero

A When transistor is cut off, IC is zero.

In a transistor E mode the collector current with the transistor in cut off region is A. zero B. high C. equal to saturated value D. none of the above

D Lowest value of β should be used to locate Q point.

In a transistor the minimum and maximum values of βdc are 100 and 121. The proper value of βdc to be used to locate Q point is A. 100 B. 121 C. 110.5 D. 110

In a two stage CE amplifier circuit, the ac collector resistance of the first stage depends on A. load resistance B. input impedance of first stage C. input impedance of second stage D. all of the above

In a typical IC monostable multivibrator circuit, at the falling edge of the trigger input, the output switches HIGH for a period of time determined by the ________. A. value of the RC timing components B. amplitude of the input trigger C. frequency of the input trigger D. magnitude of the dc supply voltage

A Capacitance is inversely proportional to distance between plates.

In a varactor diode the increase in width of depletion layer results in A. decrease in capacitance B. increase in capacitance C. no change in capacitance D. either (a) or (b)

In a voltage regulated power supply the zener operates in the breakdown region when (Vin is input voltage and Vz is zener breakdown voltage) A. Vin < Vz B. Vin > Vz C. Vin = Vz D. both (a) or (b)

In a voltage regulator network (Figure 2.117) with fixed R and RL, what element dictates the maximum level of source voltage? A. VZ B. IZM C. IZ D. none of the above

In a voltage regulator network with fixed RL and R, what element dictates the minimum level of source voltage? A. VZ B. IZ C. IZM D. none of the above

In a voltage-divider circuit, which one of the stability factors has the least effect on the device at very high temperature? A. S(ICO) B. S(VBE) C. S(β) D. undefined

In a voltage-multiplier circuit, the number of diodes is directly proportional to the multiplicative voltage factor. A. True B. False

B When reverse voltage equals breakdown value it starts conducting and voltage does not increase further.

In a zener diode A. the forward current is very high B. sharp breakdown occurs at a certain reverse voltage C. the ratio v-i can be negative D. there are two p-n junctions

In active filter circuits, inductances are avoided mainly because they A. are always associated with some resistance B. are bulky and unsuitable for miniaturisation C. are non-linear in nature D. saturate quickly

A In all metals conductivity decreases (and resistance increases) with increase in temperature

In all metals A. conductivity decreases with increase in temperature B. current flow by electrons as well as by holes C. resistivity decreases with increase in temperature D. the gap between valence and conduction bands is small

In an FET circuit, ________ is normally the parameter to be determined first. A. VGS B. VDS C. VDG D. ID

In an FET transistor, the depletion region is ________ near the top of both p-type materials. A. wider B. narrower C. the same as the rest of the depletion region D. None of the above

In an SCR, the anode current consists of A. only holes B. only electrons C. both electrons and holes D. either electrons or holes

B Once SCR has been triggered the gate has no control. Only external resistance controls the anode current.

In an SCR, the anode current is controlled by A. gate current only B. external circuit only C. both gate current and external circuit D. none of the above

A All currents are assumed positive when flowing into JFET.

In an n channel JFET A. ID, IS and IG are considered positive when flowing into the transistor B. ID and IS are considered positive when flowing into transistor and IG is considered positive when flowing out of it C. ID, IS, IG are considered positive when flowing out of transistor D. IS and IG are considered positive when flowing into transistor and ID is considered positive when flowing out of it

In an n channel JFET, the gate is A. n type B. p type C. either n or p D. partially n & partially p

In an n type semiconductor the fermi level is 0.35 eV below the conduction band, the concentration of donor atoms is increased to three times. The new position of Fermi level will be A. 0.35 eV below conduction band B. about 0.32 eV below conduction band C. about 0.32 eV above conduction band D. about 0.1 eV below conduction band

In an n-channel depletion-type MOSFET the region of positive gate voltages on the drain or transfer characteristics is referred to as the ________ region with the region between cutoff and the saturation level of ID referred to as the ________ region. A. depletion, enhancement B. enhancement, enhancement C. enhancement, depletion D. None of the above

In an n-channel enhancement-type MOSFET with a fixed value of VT, the ________ the level of VGS, the ________ the saturation level for VDS. A. higher, more B. higher, less C. lower, lower D. None of the above

In an ordinary thyristor A. turn on and turn off times are equal B. turn on time is more than turn off time C. turn off time is more than turn on time D. turn on time may be equal, less than or more than turn off time

In auxiliary commutated chopper, the charging and discharging time of capacitor A. are constant B. depend on load current C. may be constant or may depend on load current D. none of the above

In auxiliary commutated chopper, the peak value of thyristor current is A. equal to peak value of load current B. equal to peak value of capacitor current C. sum of peak value of load current and capacitor current D. none of the above

In brushless excitation system of modern alternators, the main exciter is A. dc generator B. ac generator C. either dc or ac generator D. induction generator

C The output voltage is controlled ac.

In controlled heating circuits, thyristors act as A. rectifier B. inverter C. ac regulator D. chopper

In degenerate p type semiconductor material, the Fermi level, A. is in the valence band B. is in conduction band C. is at the centre in between valence and conduction bands D. is very near conduction band

D Input ac is rectified and then converted to high frequency ac.

In dielectric heating, the thyristor circuits consist of A. rectifier-chopper combination B. controlled rectifier C. ac regulator D. rectifier-inverter combination

In disc mounting of SCR A. SCR is clamped on one side of disc shaped heat sink B. SCR is clamped between two disc shaped heat sinks C. The SCR has low current rating D. None of the above

In full wave rectification, if the input frequency is 50 Hz, then frequency at the output of filter is A. 50 Hz B. 0 Hz C. 100 Hz D. 75 Hz

In general, LEDs operate at voltage levels from _____ V to _____ V. A. 1.0, 3.0 B. 1.7, 3.3 C. 0.5, 4.0 D. none of the above

In integral cycle control of ac regulator, the input power factor is equal to A. duty cycle a B. a^2 C. SQRTa D. (a)^1/3

In integral cycle control of ac regulators, the period of integral cycle control, i.e., (m + n) T should be A. less than mechanical or thermal time constant of the system B. more than the mechanical or thermal time constant of the system C. more or less than the mechanical or thermal time constant D. very high

In integral cycle control the period of on-off control should be more than mechanical time constant of load. A. True B. False

In load commutated chopper, the commutating element A. is capacitor B. is capacitor and inductor C. is capacitor, inductor and auxiliary thyristor D. any of the above depending on load

In n-type material the _____ is called the majority carrier. A. electron B. hole C. proton D. neutron

B Emitter is p-type in p-n-p transistor. Therefore holes are majority carriers.

In p-n-p transistor the current IE has two components viz. IEP due to injection of holes from p-region to n-region and IE due to injection of electrons from n-region to p-region. Then A. IEp and IEn are almost equal B. IEp >> IEn C. IEn >> IEp D. either (a) or (c)

In pulse width modulation of chopper A. T is kept constant and Ton is varied B. Ton is kept constant T is varied C. both T and Ton are varied D. either T or Ton is varied

In register index addressing mode the effective address is given by A. index register value B. sum of the index register value and the operand C. operand D. difference of the index register value and the operand

D The input current during positive half cycle is less than that during negative half cycle.

In single phase half wave regulator, the average current over one full cycle A. is always positive B. may be positive or negative C. may be negative D. is always negative

In sinusoidal PWM for inverters the width of different pulses are not the same. A. True B. False

In the active region, while the collector-base junction is _____-biased, the base-emitter is _____-biased. A. forward, forward B. forward, reverse C. reverse, forward D. reverse, reverse

In the atomic lattice the _____ and _____ form the nucleus. A. electrons, neutrons B. electrons, protons C. neutrons, protons D. none of the above

In the automatic reset circuit for a flip-flop, how long does it take the capacitor to completely charge? A. 1 time constant (RC) B. 2 time constants (RC) C. 5 time constants (RC) D. 10 time constants (RC)

In the basic series inverter circuit, the source current has A. low harmonic content B. high harmonic content C. low or high harmonic content depending on firing angle D. zero harmonic content

In the basic series inverter circuit, the source supplies load A. only in positive half cycle B. both in positive and negative half cycles C. only in part of positive half cycle D. in positive half cycle and part of negative half cycle

In the cutoff region the collector-base junction is ________-biased and the base-emitter junction is ________-biased for a transistor. A. reverse, forward B. forward, reverse C. reverse, reverse D. forward, forward

D The min terms are A^BC + ABC + AB^ C^ + AB^C + ABC^.

In the expression A + BC, the total number of minterms will be A. 2 B. 3 C. 4 D. 5

In the given figure, A = B = 1 and C = D = 0. Then Y = A. 1 B. 0 C. either 1 or 0 D. indeterminate

In the n-channel transistor, the drain and source are connected to the ________ channel while the gate is connected to the two layers of ________ material. A. p-type, n-type B. p-type, p-type C. n-type, p-type D. n-type, n-type

In thermal ohm's law, temperature and power loss are analogous to A. V and I respectively of ohm's law B. I and V respectively of ohm's law C. R and V respectively of ohm's law D. I and R respectively of ohm's law

In troubleshooting a DAC, we check its performance characteristics, such as ________. A. nonmonotonicity B. differential nonlinearity C. low and high gain D. all of the above

In what decade was the first transistor created? A. 1930s B. 1940s C. 1950s D. 1960s

In what decade was the first transistor discovered? A. 1930s B. 1940s C. 1950s D. 1960s

In what state is a silicon diode if the voltage drop across it is about 0.7 V? A. no bias B. forward bias C. reverse bias D. Zener region

B Since propagation delays of all flip-flops are added in ripple counter, the maximum frequency depends on the number of flip-flops which depends on modulus.

In which counter does the maximum frequency depend on the modulus? A. Synchronous B. Ripple C. Both synchronous and ripple D. Neither synchronous nor ripple

In which device does the extent of light controls the conduction A. photovoltaic cell B. photo electric relay C. LED D. photo sensitive device

In which of the following color(s) is (are) LEDs presently available? A. yellow B. white C. orange D. all of the above

In which of the following is the light intensity measured? A. candela B. efficacy C. flux D. illumination

In which of the following is the width of junction barrier very small? A. Tunnel diode B. Photo diode C. PIN diode D. Schottky diode

C In schottky diode there is no charge storage and hence almost zero reverse recovery time.

In which of these is reverse recovery time nearly zero? A. Zener diode B. Tunnel diode C. Schottky diode D. PIN diode

In which region are both the collector-base and base-emitter junctions forward-biased? A. Active B. Cutoff C. Saturation D. All of the above

In which region are both the collector-base and base-emitter junctions forward-biased? A. active B. cutoff C. saturation D. all of the above

In which region of a CE bipolar transistor is collector current almost constant? A. Saturation region B. Active region C. Breakdown region D. Both saturation and active region

B It uses high frequency inverter.

Induction heating systems require low frequency inverters. A. True B. False

Instructions that allow direct control of the processor's flags are called ________ instructions. A. data transfer B. arithmetic C. bit manipulation D. processor control

Internally, a computer's binary data are almost always transmitted on parallel channels, commonly referred to as the: A. parallel bus B. serial bus C. data bus D. memory bus

Introducing those impurity elements that have _____ valence electrons creates the n-type material. A. 0 B. 3 C. 4 D. 5

Inverters find applications in A. HVDC transmission B. UPS C. variable speed ac drives D. all of the above

D One filter reduces ripple to 0.15 of initial value. The second filter reduces ripple to 0.15 x 0.15 of initial value.

It has been found that in a rectifier circuit with RC filter one RC section reduces ripple by 15%. Two RC sections are used in cascade the reduction in ripple would be A. 15% B. 30% C. 150% D. 225%

It is best not to leave unused TTL inputs unconnected (open) because of TTL's ________. A. noise sensitivity B. low-current requirement C. open-collector outputs D. tristate construction

It is desirable to design a bias circuit that is independent of the transistor beta. A. True B. False

It is desired to display the digit 7 using a seven segment display. The LEDs to be turned on are A. a, b, c B. b, c, d C. c, d, e D. a, b, d

It is not uncommon for a germanium diode with an Is in the order of 1-2 A at 25ºC to have leakage current of 0.1 mA at a temperature of 100ºC. A. True B. False

It is possible to use a freewheeling diode in A. single phase half wave controlled rectifier as well as in single phase full wave controlled rectifier (M - 2 connection) B. single phase half wave controlled rectifier but not in single phase full wave controlled rectifier (M - 2 connection) C. single phase full wave controlled rectifier (M - 2 connection) but not in single phase half wave controlled rectifier D. all controlled rectifier circuits

It is the insulating layer of _____ in the MOSFET construction that accounts for the very desirable high input impedance of the device. A. SiO B. GaAs C. SiO2 D. HCl

Karnaugh map can not be drawn when the number of variables is more than 4 A. True B. False

Lead mounting for SCR is used for A. rating less than mA B. rating about 1 A or less C. rating of 20 A or less than 20 A D. rating 100 A or less

List the categories of clippers. A. series B. parallel C. series and parallel D. none of the above

List the terminal(s) of a field-effect transistor (FET). A. drain B. gate C. source D. all of the above

List the types of bipolar junction transistors. A. ppn, npn B. pnp, npn C. npp, ppn D. nnp, pnp

Logic circuits that are designated as buffers, drivers, or buffer/drivers are designed to have: A. a greater current/voltage capability than an ordinary logic circuit. B. greater input current/voltage capability than an ordinary logic circuit. C. a smaller output current/voltage capability than an ordinary logic. D. greater input and output current/voltage capability than an ordinary logic circuit.

Logic hardware is available only in NAND and NOR. A. True B. False

Look up the propagation delay from the clock to the output for the 7476. Are the HIGH-to-LOW and LOW-to-HIGH propagation delays the same? A. yes B. no, tPLH = 25 ns, tPHL = 40 ns C. no, tPLH = 40 ns, tPHL = 25 ns D. no, tPHL = 25 ns, tPLH = 40 ns

A A + B + C = 000 = M0 .

Maxterm designation for A + B + C is A. M0 B. M1 C. M3 D. M4

Mc Murray full bridge inverter uses A. 4 thyristors and 2 diodes B. 4 thyristors and 4 diodes C. 8 thyristors and 4 diodes D. 8 thyristors and 8 diodes

McMurrary full bridge inverter uses A. auxiliary commutation B. complementary commutation C. natural commutation D. any of the above

McMurray Bedford full bridge inverter uses A. natural commutation B. auxiliary commutation C. complementary commutation D. any of the above

B If a potential difference is developed across a current carrying metal strip when the strip is placed in transverse magnetic field. Hall effect is very weak in metals, but it is large semiconductors.

Measurement of Hall coefficient enables the determination of A. recovery time of stored carrier B. type of conductivity and concentration of charge carriers C. temperature coefficient and thermal conductivity D. Fermi level and forbidden energy gap

Measurement of hall coefficient enables the determination of A. mobility of charge carriers B. type of conductivity and concentration of charge carriers C. temperature coefficient and concentration of charge carriers D. fermi level and forbidden energy gap

Minimum number of 2-input NAND gates required to implement the function F = (x^ + y^) (Z + W) is A. 3 B. 4 C. 5 D. 6

Modified Mc Murray full bridge inverter uses A. 4 thyristors and 2 diodes B. 4 thyristors and 4 diodes C. 8 thyristors and 4 diodes D. 8 thyristors and 8 diodes

Most TTL logic used today is some form of ________. A. Schottky TTL B. tristate TTL C. low-power TTL D. open-collector TTL

Most specification sheets are broken down into _____. A. maximum ratings B. thermal characteristics C. electrical characteristics D. all of the above

Multiphase choppers are used in A. low power circuits B. high power circuit C. both low and high power circuits D. medium power circuits

The two basic types of bipolar transistors are: diode and triode types NPN and PNP types varicap and zener types P and N channel types

NPN and PNP types

Natural commutation can be used in : A. DC circuits only B. AC circuits only C. both AC and DC circuits D. none of the above

B It has no effect on noise originating at amplifier input.

Negative feedback reduces noise originating at the amplifier input. A. True B. False

Normal operation of an NPN bipolar transistor requires the base to be ________ with respect to the emitter, and ________ with respect to the collector. A. positive, negative B. positive, positive C. negative, positive D. negative, negative

Octal number 12 is equal to decimal number A. 8 B. 9 C. 10 D. 11

Of the methods listed, the fastest A/D conversion is done by a ________. A. single-slope ramp converter B. dual-slope ramp converter C. successive-approximation converter D. tracking converter

B Any number of taps are possible.

On load tap changer using thyristors can have a maximum of two taps. A. True B. False

One advantage that MOSFET transistors have over bipolar transistors is ________. A. high input impedance B. higher switching speed C. low input impedance D. reduced propagation delay

One eV is equal to _____ J. A. 6.02 x 1023 B. 1.6 x 10-19 C. 6.25 x 1018 D. 1.66 x 10-24

One example for the use of a Schmitt trigger is as a(n): A. switch debouncer B. racer C. astable oscillator D. transition pulse generator

One of the most important characteristics of the FET is its ________ impedance. A. low input B. medium input C. high input D. None of the above

One output structure of a TTL gate is often referred to as a ________. A. totem-pole arrangement B. diode arrangement C. JBT arrangement D. base, emitter, collector arrangement

A Preset and clear inputs are not applied in any fixed sequence.

Out of S, R, J, K, Preset, Clear inputs to flip flops, the synchronous inputs are A. S, R, J, K only B. S, R, Preset, Clear only C. Preset, Clear only D. S, R only

B This the main difference between latch and flip-flop. Only flip-flop has clock input.

Out of latch and flip flop, which has clock input? A. Latch only B. Flip flop only C. Both latch and flip flop D. None

C A phase shifter gives two voltages which have equal magnitudes but are out of phase by 180°.

Output of a phase splitter is A. a pair of sine waves of unequal amplitude B. a pair of sine waves of equal amplitudes C. a pair of sine waves of equal amplitudes and opposite phase D. a pair of sine waves of unequal amplitudes and opposite phase

P-MOS and N-MOS ________. A. represent MOSFET devices utilizing either P-channel or N-channel devices exclusively within a given gate B. are enhancement-type CMOS devices used to produce a series of high-speed logic known as 74HC C. represent positive and negative MOS-type devices that can be operated from differential power supplies and are compatible with operational amplifiers D. None of the above are.

PMOS and NMOS ________. A. represent MOSFET devices utilizing either P-channel or N-channel devices exclusively within a given gate B. are enhancement-type CMOS devices used to produce a series of high-speed logic known as 74HC C. represent positive and negative MOS-type devices, which can be operated from differential power supplies and are compatible with operational amplifiers D. None of the above

PMOS and NMOS circuits are used largely in ________. A. MSI functions B. LSI functions C. diode functions D. TTL functions

Parallel adder is A. sequential circuit B. combinational circuit C. either sequential or combinational circuit D. none of the above

B Adder is a combinational circuit.

Parallel adder is A. sequential circuit B. combinational circuit C. either sequential or combinational circuit D. none of the above

Parity systems are defined as either________ or ________ and will add an extra ________ to the digital information being transmitted. A. positive, negative, byte B. odd, even, bit C. upper, lower, digit D. on, off, decimal

B The frequency of incident radiation has to be more than threshold value. Wavelength is inversely proportional to frequency. Therefore wavelength of incident radiation must be less than threshold value.

Photo electric emission can occur only if A. wave length of incident radiation is equal to threshold value B. wave length of incident radiation is less than threshold value C. frequency of incident radiation is less than threshold frequency D. none of the above

Photoconductive devices uses A. metallic conductors B. good quality insulators C. semiconductors D. either (a) or (c)

Polled I/O works best when ________. A. there are no priority considerations B. priority considerations are frequent C. the polling rate exceeds 1000 s D. the polling rate is below 1000 s

D In oscillators, the oscillations are generated due to positive feedback. In thyristors anode current increases due to positive feedback.

Positive feedback is mainly used in A. oscillators B. thyristors C. voltage regulators D. both (a) and (b)

Present day HVDC converters are all A. 3 pulse converters B. 6 pulse converters C. 12 pulse converters D. either 6 pulse or 12 converters

Propagation delay is important because ________. A. the logic gates must be given a short break during each clock cycle or else they will overheat B. it limits the maximum operating frequency of a gate C. it is a measure of how long the clock must be applied to the gate before it will make the required decision D. all the gates in a system must have the same propagation times in order to be compatible

If alternating current is applied to the anode of a diode, what would you expect to see at the cathode? No signal Steady direct current Pulsating direct current Pulsating alternating current

Pulsating direct current

Pulse stretching, time-delay, and pulse generation are all easily accomplished with which type of multivibrator circuit? A. astable B. monostable C. multistable D. bistable

B Due to recombination the number of electron-hole pairs is reduced.

Recombination produces new electron-hole pairs A. True B. False

Rectifiers are commonly used in battery chargers. A. True B. False

Refer to Figure 2.115. With the Zener diode in the "on state", what is the level of IZ for the maximum load resistor Rmax? A. 0 mA B. undefined C. equal to IRL D. IZM

Refer to Figure 2.18. Determine the current level if E = 15 V and R = 3 k. A. 0 A B. 4.76 mA C. 5 mA D. 5 A

Refer to Figure 2.18. Determine the voltage across the resistor if E = 0.2 V. A. 0 V B. 0.09 V C. 0.2 V D. 0.44 V

Refer to Figure 2.23. Determine the new value of the load resistor if ID = 2 mA. A. 5 k B. 5.5 k C. 6 k D. none of the above

Refer to Figure 2.40. What is the logic function of the circuit? A. Positive logic AND gate B. Positive logic OR gate C. Negative logic AND gate D. Negative logic OR gate

Refer to Figure 2.43. What is the logic function of the circuit? A. Positive logic AND gate B. Positive logic OR gate C. Negative logic AND gate D. Negative logic OR gate

Refer to Figure 2.45. What best describes the circuit? A. full-wave rectifier B. half-wave rectifier C. clipper D. clamper

Refer to Figure 2.54. What best describes the circuit? A. full-wave rectifier B. half-wave rectifier C. clipper D. clamper

Refer to Figure 2.70. What best describes the circuit? A. full-wave rectifier B. half-wave rectifier C. clipper D. clamper

Refer to Figures 2.3a and 2.4. Determine the value of IDQ if E = 5 V. A. 0 mA B. 4.1 mA C. 5 mA D. 10 mA

Refer to the table. Calculate the change in IC from 25ºC to 175ºC for RB /RE = 250 due to the S(ICO) stability factor. A. 140.34 nA B. 140.34 μA C. 42.53 nA D. 0.14034 nA

Resistivity of hard drawn copper is A. less than that of annealed copper B. more than that of annealed copper C. same as that of annealed copper D. decreasing when temperature increases

SCR can be turned on by 1. applying anode voltage at a sufficient fast rate 2. applying sufficiently large anode voltage 3. increasing the temperature of SCR to a sufficiently 4. applying sufficiently large gate current. A. 1, 2, 4 only B. 4 only C. 1, 2, 3, 4 D. none

Secondary emission is always decremental. A. True B. False

Select the statement that best describes the parity method of error detection: A. Parity checking is best suited for detecting double-bit errors that occur during the transmission of codes from one location to another. B. Parity checking is not suitable for detecting single-bit errors in transmitted codes. C. Parity checking is best suited for detecting single-bit errors in transmitted codes. D. Parity checking is capable of detecting and correcting errors in transmitted codes.

Serial communication can be sped up by: A. using silver or gold conductors instead of copper B. using high-speed clock signals C. adjusting the duty cycle of the binary information D. using silver or gold conductors instead of copper and high-speed clock signals

Settling time is normally defined as the time it takes a DAC to settle within ________. A. 1/8 LSB of its final value when a change occurs in the input code B. 1/4 LSB of its final value when a change occurs in the input code C. 1/2 LSB of its final value when a change occurs in the input code D. 1 LSB of its final value when a change occurs in the input code

Setup time specifies: A. the minimum time the control levels need to be maintained on the inputs prior to the triggering edge of the clock in order to be reliably clocked into the flip-flop B. the maximum time interval required for the control levels to remain on the inputs before the triggered edge of the clock in order for the data to be reliably clocked out of the flip-flop C. how long the operator has to get the flip-flop running before the maximum power level is exceeded D. how long it takes the output to change states after the clock has transitioned

Several manufacturers have developed logic that combines the best features of TTL and CMOS. This is called ________. A. 12L B. BiCMOS C. 74ACT D. 74HCT

Show from the truth table how an exclusive-OR gate can be used to invert the data on one input if the other input is a special control function. A. Using A as the control, when A = 0, X is the same as B. When A = 1, X is the same as B. B. Using A as the control, when A = 0, X is the same as B. When A = 1, X is the inverse of B. C. Using A as the control, when A = 0, X is the inverse of B. When A = 1, X is the same as B. D. Using A as the control, when A = 0, X is the inverse of B. When A = 1, X is the inverse of B

Single-bit indicators that may be set or cleared to show the results of logical or arithmetic operations are the: A. flags B. registers C. monitors D. decisions

Special handling precautions should be taken when working with MOS devices. Which of the following statements is not one of these precautions? A. All test equipment should be grounded. B. MOS devices should have their leads shorted together for shipment and storage. C. Never remove or insert MOS devices with the power on. D. Workers handling MOS devices should not have grounding straps attached to their wrists.

Surge current rating of an SCR is A. the maximum repetitive surge current in which the SCR can withstand B. the maximum non-repetitive surge current in which the SCR can withstand C. the maximum repetitive or non repetitive surge current in which the SCR can withstand D. the maximum surge current in which the SCR can withstand if both surge current and steady current exist together

TTL is alive and well, particularly in ________. A. industrial applications B. educational applications C. military applications D. commercial applications

TTL logic chips must have connections to Vcc and ground, even if all inputs and outputs are properly used and tied to valid signals. A. True B. False

Ten TTL loads per TTL driver is known as: A. noise immunity B. fan-out C. power dissipation D. propagation delay

The "on" and "off" characteristics refer to ________ limits while the small-signal characteristics indicate the parameters of importance to ________ operation. A. ac, dc B. dc, ac C. ac, dc and ac D. dc and ac, dc

The 74F-Fast TTL integrated-circuit fabrication technique uses reduced interdevice ________ to achieve reduced propagation delays. A. noise B. resistance C. capacitance D. inductance

The 8085A is a(n): A. 16-bit parallel CPU B. 8-bit serial CPU C. 8-bit parallel CPU D. none of the above

The ADC0804 is an example of a ________. A. single-slope analog-to-digital converter B. dual-slope analog-to-digital converter C. digital-ramp analog-to-digital converter D. successive-approximation analog-to-digital converter

The ADD, CMP, and MUL instructions are all part of which type of instruction? A. Data transfer B. Arithmetic C. Bit manipulation D. Loops and jumps

The AND, OR, and TEST instructions are all part of which type of instruction? A. Data transfer B. Arithmetic C. Bit manipulation D. Loops and jumps

The BJT is a _____ device. The FET is a _____ device. A. bipolar, bipolar B. bipolar, unipolar C. unipolar, bipolar D. unipolar, unipolar

The Ex-NOR is sometimes called the ________. A. parity gate B. equality gate C. inverted OR D. parity gate or the equality gate

The FET resistance in the ohmic region is ________ at VP and ________ at the origin. A. smallest, largest B. largest, smallest C. larger, smaller D. smaller, larger

The HIGH logic level for a standard TTL output must be at least ________. A. 2.4 V B. 2 V C. 0.8 V D. 5 V

The IEEE/ANSI notation of an internal underlined diamond denotes: A. totem-pole outputs. B. open-collector outputs. C. quadrature amplifiers. D. tristate buffers.

The JNZ, JA, and LOOP instructions are all part of which type of instruction? A. Data transfer B. Arithmetic C. Bit manipulation D. Loops and jumps

The MOV, PUSH, and POP instructions are all part of which type of instruction? A. Data transfer B. Arithmetic C. Bit manipulation D. Loops and jumps

The Pentium can address ________. A. 1 MB B. 1 GB C. 2 GB D. 4 GB

The Pentium microprocessor has a data bus of ________. A. 16 bits B. 32 bits C. 64 bits D. 128 bits

The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply of frequency of A. 30 kHz B. 15 kHz C. 5 kHz D. 20 kHz

The TTL HIGH level source current is higher than the LOW level sinking current. A. True B. False

The _____ diode model is employed most frequently in the analysis of electronic systems. A. ideal device B. simplified C. piecewise-linear

The _____ the current through a diode, the _____ the dc resistance level. A. higher, lower B. lower, lower C. lower, higher D. higher, higher

The ________ circuit overcomes the problem of switching caused by jitter on the inputs. A. astable multivibrator B. monostable multivibrator C. bistable multivibrator D. Schmitt trigger

The ________ ensures that only one IC is active at a time to avoid a bus conflict caused by two ICs writing different data to the same bus. A. control bus B. control instructions C. address decoder D. CPU

The ________ is defined as the maximum number of standard logic inputs that an output can drive reliably. A. fan-drive B. fan-out C. fan-in D. open-collector

The ________ is defined as the time the output is active divided by the total period of the output signal. A. on time B. off time C. duty cycle D. active ratio

The ________ region is the region normally employed for linear (undistorted) amplifiers. A. active B. cutoff C. saturation D. All of the above

The ________ transistor has become one of the most important devices used in the design and construction of integrated circuits for digital computers. A. MOSFET B. BJT C. JFET D. None of the above

The ac resistance of a diode is the _____ of the characteristic curve at the Q-point of operation. A. reciprocal of the slope B. slope C. midpoint D. average value

B Access time = 0.95 x 10 + 0.05 x 100.

The access time of a word in 4 MB main memory is 100 ms. The access time of a word in a 32 kb data cache memory is 10 ns. The average data cache bit ratio is 0.95. The efficiency of memory access time is A. 9.5 ns B. 14.5 ns C. 20 ns D. 95 ns

The active region of a transistor is bounded by the ________. A. cutoff region B. saturation region C. power dissipation curve D. All of the above

The active region of an FET is bounded by ________. A. ohmic region B. cutoff region C. power line D. All of the above

The active switching element used in all TTL circuits is the ________. A. bipolar junction transistor (BJT) B. field-effect transistor (FET) C. metal-oxide semiconductor field-effect transistor (MOSFET) D. unijunction transistor (UJ)

The advantage of modified series inverter with two inductors and two capacitors is A. the intermittent operation of battery is avoided B. efficiency of circuit is more C. the output frequency is low D. all of the above

The amount of dielectric heating is inversely proportional to frequency. A. True B. False

B Only the intensity of incident radiation governs the amount of photoelectric emission.

The amount of photoelectric emission current depends on A. frequency of incident radiation B. intensity of incident radiation C. both frequency and intensity of incident radiation D. none of the above

The application of gate signal decreases the break over voltage of on SCR. A. True B. False

A The firing angle controls the period of conduction and hence average load current.

The average load current supplied by a thyristor depends on A. firing angle B. firing frequency C. magnitude of gate current D. all of the above

A Storing can be done only in memory and flip-flop is a memory element.

The basic storage element in a digital system is A. flip flop B. counter C. multiplexer D. encoder

D Both JFET and vacuum triode are voltage controlled devices.

The behaviour of a JFET is similar to that of A. NPN transistor B. PNP transistor C. SCR D. Vacuum triode

The bipolar TTL logic family that was developed to increase switching speed by preventing transistor saturation is: A. emitter-coupled logic (ECL). B. current-mode logic (CML). C. transistor-transistor logic (TTL). D. emitter-coupled logic (ECL) and transistor-transistor logic (TTL).

The breakdown voltage in a zener diode A. is almost constant B. is very small C. may destroy the diode D. decreases with increase in current

The channel of JFET consists of A. p type material only B. n type material only C. conducting material D. either p or n type material

The characteristics of a non-linear resistance is i = kv^4. If i becomes 100 times, v becomes A. about 100 times B. about 10 times C. about 3 times D. about twice

The circuit of the given figure is A. full adder B. full subtractor C. shift register D. decade counter

The circuit of the given figure realizes the function A. Y = (A + B) C + DE B. Y = A + B + C + D + E C. AB + C +DE D. AB + C(D + E)

The circuits in the 8085A that provide the arithmetic and logic functions are called the: A. CPU B. ALU C. I/O D. none of the above

The common-collector configuration has a ________ input impedance and a ________ output impedance. A. low, high B. high, low C. high, high D. low, low

The commutation method in an inverter, is A. line commutation B. forced commutation C. either (a) or (b) D. none of the above

B Minority carriers are generated due to thermal excitation.

The concentration of minority carriers in a semiconductor depends mainly on A. the extent of doping B. temperature C. the applied bias D. none of the above

The condition of a semiconductor diode can be determined quickly using a _____. A. DDM B. VOM C. curve tracer D. any of the above

The control bus and memories share a bidirectional bus in a typical microprocessor system. A. True B. False

B When counter is 110 the counter resets. Hence mod 6.

The counter in the given figure is A. Mod 3 B. Mod 6 C. Mod 8 D. Mod 7

The coupling capacitor in amplifier circuits A. affects dc biasing B. does not affect dc biasing C. affects dc biasing to some extent D. both (a) and (c)

The cutoff region is defined by IB _____ 0 μA A. > B. < C. ≤ D. ≥

D Since both diodes contribute equal load current, each diode current is 5 mA.

The dc load current in a bridge rectifier circuit is 10 mA. The dc load current through each diode is A. 40 mA B. 20 mA C. 10 mA D. 5 mA

The density of dynamic RAM is A. the same as static RAM B. less than that of static RAM C. more than that of static RAM D. either equal or less than that of static RAM

The depletion layer around p-n junction in JFET consists of A. hole B. electron C. immobile charges D. none of the above

The depletion width _____ in the forward bias, which results in having a majority flow across the junction. A. widens B. remains unchanged C. shrinks D. widens and shrinks alternatively

The derating factor for a BJT transistor is about A. 0.5 mW/°C B. 2.5 mW/°C C. 10 mW/°C D. 25 mW/°C

The devices that provide the means for a computer to communicate with the user or other computers are referred to as: A. CPU B. ALU C. I/O D. none of the above

The diameter of an atom is A. 10-6 metre B. 10-10 metre C. 10-15 metre D. 10-21 metre

The difference between resonant commutation and self commutation is A. both these methods are based on entirely different principles B. in resonant commutation, the commutating elements carry load current but in self commutation, the commutating elements do not carry load current C. resonant commutation uses L and C but self commutation uses only capacitor D. none of the above

The diffused impurities with _____ valence electrons are called acceptor atoms. A. 0 B. 3 C. 4 D. 5

The diffused impurities with _____ valence electrons are called donor atoms. A. 4 B. 3 C. 5 D. 0

The diode _____. A. is the simplest of semiconductor devices B. has characteristics that closely match those of a simple switch C. is a two-terminal device D. all of the above

A The drift is amplified by different stages.

The disadvantage of direct coupled amplifiers is A. drift B. large size of transistor C. low voltage gain D. both (b) and (c)

The dissipation at the collector is in the quiescent state and increases with excitation in the case of a A. class A series fed Amplifier B. class A transistor coupled Amplifier C. class AB amplifier D. class B amplifier

The doping of the sandwiched layer is ________ that of the outer layers. A. considerably less than B. the same as C. considerably more than D. None of the above

The drain characteristics of JFET in operating region, are A. inclined upwards B. almost flat C. inclined downwards D. inclined upwards or downwards

The drain current will always be one-fourth of IDSS as long as the gate-to-source voltage is _____ the pinch-off value. A. one-fourth B. one-half C. three-fourths D. none of the above

The dual-slope analog-to-digital converter finds extensive use in ________. A. digital voltmeters B. function generators C. frequency counters D. all of the above

B Discharge current flows through Re .

The dynamic equalising circuit consists of a series combination of capacitor C and resistor RC across each thyristor. This resistance RC (along with parallel connected diode) A. limits charging current B. limits discharging current C. limits both charging and discharging currents D. none of the above

The effect of source inductance in a 3 phase fully controlled bridge converter is to A. decrease the output voltage B. increase the output voltage C. decrease the output voltage and increase the output current D. increase the output voltage and decrease the output current

The efficiency of a chopper circuit is about A. 80% or more B. around 50% C. around 20% D. around 5%

B Efficiency of full wave rectifier with centre tapped transformer is slightly higher than that of bridge rectifier.

The efficiency of a full wave rectifier using centre tapped transformer is twice that in full wave bridge rectifier. A. True B. False

The enhancement-type MOSFET is in the cutoff region if ________. A. applied VGS is larger than VGS(Th) B. applied VGS is less than or equal to VGS(Th) C. VGS has a positive level D. None of the above

The expression Y = pM (0, 1, 3, 4) is A. POS B. SOP C. Hybrid D. none of the above

The expression on the figure is equal to A. A + B + C B. ABC C. ¬ABC D. ¬(A + B + C)

The factor η for a UJT is about A. 0.1 B. 0.2 C. 0.6 D. 0.9

The family of logic that is composed of bipolar junction transistors is ____. A. TTL B. CMOS C. DIP D. BJT

The first Intel microprocessor to contain on-board cache memory was the ________. A. 80386 B. 80486 C. Pentium D. Pentium Pro

The first machine cycle of an instruction is always A. a memory read cycle B. a fetch cycle C. a input/output read cycle D. a memory write cycle

The first microprocessor had a(n)________. A. 1-bit data bus B. 2-bit data bus C. 4-bit data bus D. 8-bit data bus

The forward characteristics curve of a diode grows in _____ form. A. linear B. exponential C. logarithmic D. sinusoidal

The function Y = AC + BD + EF is A. POS B. SOP C. Hybrid D. none of the above

B Gain is proportional to gm .

The gain of an FET amplifier can be changed by changing A. rm B. gm C. Rd D. none of the above

The gate current required to turn on an SCR is A. few amperes B. a few mA C. almost equal to anode current D. about 50% of anode current

The gate lead, in a thyristor is welded to : A. p layer to which anode is connected B. n layer nearest to the anode terminal C. p layer nearest to the cathode terminal D. outside n layer

The gates G1 and G2 in the figure have propagation delays of 10 n sec. and 20 n sec. respectively. If the input Vi makes an output change from logic 0 to 1 at time t = t0 then the output waveform V0 is

The greater the propagation delay, the ________. A. lower the maximum frequency B. higher the maximum frequency C. maximum frequency is unaffected D. minimum frequency is unaffected

B The largest negative number is 1000 0000 = -128.

The greatest negative number which can be stored is 8 bit computer using 2's complement arithmetic is A. - 256 B. - 128 C. - 255 D. - 127

The heavier the current in a Zener diode in reverse bias, _____ the dynamic resistance value. A. the more B. the less C. there is substantially more D. there is no change in

The hexadecimal number (3E8)16 is equal to decimal number A. 1000 B. 982 C. 768 D. 323

The high input impedance of MOSFETs: A. allows faster switching B. reduces input current and power dissipation C. prevents dense packing D. creates low-noise reactions

A A stabilizer must give constant output voltage. This is possible only if internal resistance is low.

The ideal characteristics of a stabilizer is A. constant output voltage with low internal resistance B. constant output current with low internal resistance C. constant output voltage with high internal resistance D. constant internal resistance and constant output current

The ideal diode is a(n) _____ circuit in the region of nonconduction. A. open B. short

D Integral of a constant is t.

The input to an op-amp integrating amplifier is a constant voltage. The output will be A. a constant voltage B. a sawtooth wave C. a ramp D. ac voltage

C The amplifier in the oscillator amplifies the noise voltages. However phase shift around the closed loop is zero at only one frequency. Therefore, only this frequency appears at output.

The input voltage for starting oscillations in an oscillator is caused by A. negative feedback B. positive feedback C. noise voltage in resistors D. a special generator

The intensity of LED is greatest at _____ degrees and the least at _____ degrees. A. 0, 90 B. 45, 90 C. 0, 45 D. 90, 180

The internal circuitry of the 555 timer consists of ________, an R-S flip-flop, a transistor switch, an output buffer amplifier, and a voltage divider. A. a comparator B. a voltage amplifier C. two comparators D. a peak detector

The items that you can physically touch in a computer system are called: A. software B. firmware C. hardware D. none of the above

The leads in a TRIAC are denoted by A. anode cathode, gate B. T1 T2, gate C. T1, T2, anode D. T1, T2, T3

The leads of a transistor are typically made of ________. A. gold B. aluminum C. nickel D. All of the above

The level of VGS that results in ID = 0 mA is defined by VGS = _____. A. VGS(off) B. VP C. VDS D. none of the above

The level of VGS that results in ID = 0 mA is defined by VGS = ________. A. VGS(off) B. VP C. VDS D. None of the above

The level of ________ is determined and displayed by advanced digital meters if using diode-testing mode. A. VBE B. IC C. IB D. IE

The level of ________ is determined and displayed by advanced digital meters. A. VCE B. IB C. IC D. Bdc

The level of ________ that results in the significant increase in drain current in enhancement-type MOSFETs is called threshold voltage VT. A. VDD B. VDS C. VGS D. VDG

The load circuit of a single phase full bridge inverter A. must be underdamped B. must be overdamped C. may be underdamped or overdamped D. may be any type of load

D It is 180° for purely resistive load and between 180° and 270° for R-L load

The load impedance ZL of a CE amplifier has R and L in series. The phase difference between output and input will be A. 180° B. 0 C. more than 90° but less than 180° D. more than 180° but less than 270°

The lower doping level ________ the conductivity and ________ the resistivity of the material. A. increases, decreases B. increases, increases C. decreases, decreases D. decreases, increases

The lower transistor of a totem-pole output is saturated when the gate output is ________. A. overdriven B. HIGH C. LOW D. malfunctioning

The magnitude of the base current is typically on the order of ________ as compared to ________ for the emitter. A. uA, uA B. uA, mA C. mA, uA D. mA, mA

C Low power consumption is a big advantage in digital circuits.

The main advantage of CMOS circuit is A. high gain B. high output impedance C. low power consumption D. high gain and high output impedance

C Because of high switching speed MOSFET is very suitable for digital circuit.

The main application of enhancement mode MOSFET is in A. amplifier circuits B. oscillator circuits C. switching circuits D. all of the above

The main concern when using a pull-down resistor is: A. the low power dissipation of the resistor B. it will keep a floating terminal LOW C. the high power dissipation of the resistor D. it will cause false triggering

The main utility of SCR is due to A. gate triggering B. high temperature triggering C. DV/DT triggering D. high breakdown voltage

C IC 74193 is a divide by 16 counter. Since 4 stages are used, counting range = 164 = 65536.

The maximum counting range of a four stage counter using IC 74193 is A. 0 to 1023 B. 0 to 4093 C. 0 to 65535 D. 0 to 131071

The method of triggering SCS is A. application of positive pulse at cathode gate or negative pulse at anode gate B. application of pulse at anode gate C. application of pulse at cathode gate D. application of low voltage at anode

The minimum gate current which can turn on SCR is called : A. trigger current B. holding current C. junction current D. breakover current

The minimum input voltage recognized as HIGH by a TTL gate is ________. A. 2.0 V B. 2.4 V C. 0.8 V D. 5.0 V

A SQRT(D*TAU)

The minority carrier life time and diffusion constant in a semiconductor material are respectively 100 microsecond and 100 cm2/sec. The diffusion length is A. 0.1 cm B. 0.01 cm C. 0.0141 cm D. 1 cm

The monostable multivibrator circuit is not an oscillator because ________. A. its output switches between two states B. it requires a trigger to obtain an output signal C. it requires a sine wave input signal D. the circuit does not require a dc power supply

The most common TTL series ICs are: A. E-MOSFET B. 7400 C. quad D. AC00

A Voltage divider bias stabilizes IC.

The most commonly used bias in BJT amplifier circuits is A. voltage divider bias B. emitter bias C. collector bias D. collector feedback bias

D Oil used in transformer work as cooling as well as dielectric strength.

The most important set of specifications of transformer oil includes A. dielectric strength and viscosity B. dielectric strength and flash point C. flash point and viscosity D. dielectric strength, flash point and viscosity

The no. of comparators required in a 3 bit comparator type ADC is A. 2 B. 3 C. 7 D. 8

C Number of comparators = 2n - 1

The no. of comparators required in a 3 bit comparator type ADC is A. 2 B. 3 C. 7 D. 8

The nominal value of the dc supply voltage for TTL and CMOS is ________. A. +3 V B. +5 V C. +9 V D. +12 V

The normal operation of JFET is A. constant voltage region B. constant current region C. both constant voltage and constant current regions D. either constant voltage or constant current region

D 2^12 = 4096

The number of address lines in EPROM 4096 x 8 is A. 2 B. 4 C. 8 D. 12

The number of bits in ASCII is A. 12 B. 10 C. 9 D. 7

The number of cells in a 4 variable K map is A. 16 B. 8 C. 4 D. 32

The number of counter states which an 8 bit stair step A/D converter has to pass through before conversion takes place is equal to A. 1 B. 8 C. 255 D. 256

The number of data lines on the GPIB is ________. A. 1 B. 4 C. 8 D. 16

A The octal system has 8 digits 0 to 7.

The number of digits in octal system is A. 8 B. 7 C. 9 D. 10

D 22^n = 22^4 = 216.

The number of distinct Boolean expression of 4 variables is A. 16 B. 256 C. 1024 D. 65536

B A PIN diode has p and n doped regions separated by intrinsic layer.

The number of doped regions in PIN diode is A. 1 B. 2 C. 3 D. 1 or 2

The number of doped regions in a SCR is A. 2 B. 3 C. 4 D. 5

The number of gates that can be connected to a single output without exceeding the current ratings of the gate is called ________. A. fan-out B. propagation C. dissipation D. SSI

A Inputs are carry from lower bits and two other bits. Outputs are SUM and CARRY.

The number of inputs and outputs of a full adder are A. 3 and 2 respectively B. 2 and 3 respectively C. 4 and 2 respectively D. 2 and 4 respectively

The number of layers in a Shockley diode are A. 2 B. 3 C. 4 D. 2 or 3

The number of leads in a power semiconductor diode are A. 2 B. 3 C. 4 D. 2 or 3

The number of leads in an SCR are : A. 2 B. 3 C. 4 D. 5

The number of p-n junctions in a semiconductor diode are A. 0 B. 1 C. 2 D. 1 or 2

The number of thyristors in a single phase fully controlled bridge rectifier is A. 16 B. 8 C. 4 D. 2

The number of unused states in a 4 bit Johnson counter is A. 2 B. 4 C. 8 D. 12

C The stabilisation of gain is one of the advantages of closed loop system.

The open loop gain of an amplifier is 50 but likely to decrease by 20% due to various factors. If negative feedback with β = 0.1 is used, the change in gain will be about A. 20% B. 2% C. 0.5% D. 0.05%

The open loop gain of an ideal op-amp is A. infinite B. very high C. neither high nor low D. low

The outer layers of a transistor are ________ the sandwiched layer. A. much smaller than B. the same as C. much larger than D. None of the above

The output current capability of a single 7400 NAND gate when HIGH is called ________. A. source current B. sink current C. IOH D. source current of IOH

The output current for a LOW output is called a(n) ________. A. sink current B. ground current C. exit current D. fan-out

The output frequency of a cycloconverter can be changed by changing the firing angle. A. True B. False

The output of a half adder is A. SUM B. CARRY C. SUM and CARRY D. none of the above

The output of a standard TTL NAND gate is used to pull an LED indicator LOW. The LED is in series with a 470- resistor. What is the current in the circuit when the LED is on? A. 7.02 mA B. 8.51 mA C. 10.63 mA D. 5.32 mA

The output of the astable circuit ________. A. constantly switches between two states B. is LOW until a trigger is received C. is HIGH until a trigger is received D. floats until triggered

The output stage of a TTL gate is a special design called ________. A. multiemitter B. totem-pole C. MSI D. DIP

C Due to direct coupling between output and CRO both dc and ac output voltage will appear on screen of CRO.

The output voltage waveform of a CE amplifier is fed to a dc coupled CRO. The trace on the screen will be A. dc output voltage B. ac output voltage C. sum of dc and ac output voltage D. either (a) or (b)

The output wave of a cycloconverter consists of a number of segments derived from the input wave. A. True B. False

The parameter h11 for CB circuit is higher than that for CE circuit. A. True B. False

B Source inductance delays turn off and hence causes overlap.

The phenomenon of overlap in converter operation due to A. source resistance B. source inductance C. both source resistance and source inductance D. high value of firing angle

The pinch-off voltage continues to drop in a ________ manner as VGS becomes more and more negative. A. linear B. parabolic C. cubic D. None of the above

The potential at which the characteristics curve vertical rise occurs is commonly referred to as the _____. A. offset B. threshold C. firing potential D. all of the above

C Maximum power dissipation occurs at collector junction.

The power dissipation in a transistor is the product of A. emitter current and emitter to base voltage B. emitter current and collector to emitter voltage C. collector current and collector to emitter voltage D. none of the above

The power dissipation of a CMOS IC will ________. A. decrease with frequency B. increase with gate size C. decrease with gate size D. increase with frequency

The power factor at the input terminals of a cyclo- converter is generally A. low and leading B. low and lagging C. high and leading D. high and lagging

The primary difference between the construction of a MOSFET and an FET is the ________. A. construction of the gate connection B. low input impedance C. threshold voltage D. None of the above

The primary difference between the construction of depletion-type and enhancement-type MOSFETs is ________. A. the size of the transistor B. the absence of the channel C. the reverse bias junction D. All of the above

The principal advantage of the three-wire handshake on the GPIB is that it ________. A. is faster than two-wire methods B. allows fast and slow listeners on the same bus C. can be used over very long distances D. is compatible with the RS232C standard

The problem of different current requirements when CMOS logic circuits are driving TTL logic circuits can usually be overcome by the addition of: A. a CMOS inverting bilateral switch between the stages B. a TTL tristate inverting buffer between the stages C. a CMOS noninverting bilateral switch between the stages D. a CMOS buffer or inverting buffer

The problem of interfacing IC logic families that have different supply voltages (VCC's) can be solved by using a: A. level-shifter B. tristate shifter C. decoupling capacitor D. pull-down resistor

The problem of the VOH(min) of a TTL IC being too low to drive a CMOS circuit and meet the CMOS requirement of VIH(min) is usually easily overcome by: A. adding a fixed voltage-divider bias resistive network at the output of the TTL device B. avoiding this condition and only using TTL to drive TTL C. adding an external pull-down resistor to ground D. adding an external pull-up resistor to VCC

The process of jointly establishing communication is called ________. A. DMA B. bidirectional addressing C. multiplexing D. handshaking

The proliferation of small handheld consumer equipment such as digital video cameras, cellular phones, handheld computers (________), portable audio systems, and other devices has created a need for logic circuits in very small packages. A. HDLs B. GDAs C. PDAs D. TTLs

The propagation delay of standard TTL gates is approximately ________. A. 2 us B. 1 us C. 4 ns D. 10 ns

The pulse width out of a one-shot multivibrator increases when the: A. supply voltage increases B. timing resistor decreases C. UTP decreases D. timing capacitance increases

The purpose of a pull-up resistor is to keep a terminal at a ________ level when it would normally be at a ________ level. A. LOW, float B. HIGH, float C. clock, float D. pulsed, float

A Quiescent-operation means operation when ac signal is not applied.

The quiescent collector current IC, and collector to emitter voltage VCE in a CE connection are the values when A. ac signal is zero B. ac signal is low C. ac signal is negative D. either (a) or (b)

D The holding current is much less then 1% of rated current.

The rated current of a thyristor is 40 A. The holding current will be about : A. 20 A B. 1 A C. 100 mA D. 10 mA

The ratio of which two currents is represented by β? A. IC and IE B. IC and IB C. IE and IB D. none of the above

The region to the left of the pinch-off locus is referred to as the _____ region. A. saturation B. cutoff C. ohmic D. all of the above

The region to the left of the pinch-off locus is referred to as the ________ region. A. saturation B. cutoff C. ohmic D. All of the above

The region to the right of the pinch-off locus is commonly referred to as the ________ region. A. constant-current B. saturation C. linear amplification D. All of the above

The register in the 8085A that is used to keep track of the memory address of the next op-code to be run in the program is the: A. stack pointer B. program counter C. instruction pointer D. accumulator

The resolution of a 6-bit DAC is ________. A. 63% B. 64% C. 15.9% D. 1.59%

The resolution of a DAC can be expressed as the ________. A. minimum output voltage B. number of bits that are converted to an analog output C. deviation of the output from a straight line D. difference between the expected and actual outputs

The resolution of an n bit DAC with a maximum input of 5 V is 5 mV. The value of n is A. 8 B. 9 C. 10 D. 11

The reverse recovery time of most commercial switching diodes is in the range of _____. A. picoseconds B. a few nanoseconds C. several microseconds D. milliseconds

The reverse saturation current Is will just _____ in magnitude for every 10º C increase in temperature. A. double B. remain the same C. halve D. triple

The reverse-bias current _____ with the increase of temperature. A. decreases B. increases C. remains the same D. none of the above

The reverse-bias current level is typically measured in _____. A. pA B. μA C. mA D. A

B Ripple factor of half wave rectifier is 1.21 .

The ripple factor of a half wave rectifier is more than 2. A. True B. False

The rise time (tr) is the time it takes for a pulse to rise from its ________ point up to its ________ point. The fall time (tf) is the length of time it takes to fall from the ________ to the ________ point. A. 10%, 90%, 90%, 10% B. 90%, 10%, 10%, 90% C. 20%, 80%, 80%, 20% D. 10%, 70.7%, 70.7%, 10%

The saturation region is defined by VCE _____ VCEsat. A. > B. < C. ≤ D. ≥

The self bias provides A. stable Q point B. large voltage gain C. high input impedance D. high base current

The serial format for transmitting binary information uses: A. a single conductor B. multiple conductors C. infrared technology D. fiber-optic

The silicon dioxide (SiO2) layer used in a MOSFET is ________. A. an insulator B. a conductor C. a semiconductor D. None of the above

The slew rate of an ideal op-amp is A. very slow B. slow C. fast D. infinitely fast

The snubber circuit consists of A. a capacitor connected in series with thyristor B. a capacitor connected in parallel with thyristor C. a resistor and capacitor in series connected across thyristor D. none of the above

The software used to drive microprocessor-based systems is called: A. assembly language B. firmware C. machine language code D. BASIC interpreter instructions

The specified maximum junction temperature of thyristors is about A. 50°C B. 80°C C. 120°C D. 200°C

The static characteristic of an adequately forward biased P-n junction is a straight line, if the plot is of __________ Vs → versus A. log I Vs log V B. log I Vs V C. I Vs log V D. I Vs V

The static equalisation circuit for thyristors connected in series is A. one resistor in series with each thyristor B. one resistor in parallel with each thyristor C. one resistor and one capacitor in parallel with each thyristor D. none of the above

The step function (per step) of a curve tracer reveals the scale for ________. A. collector current IC B. VCE voltage C. base current IB D. All of the above

The stud in a stud mounted SCR acts as A. anode B. cathode C. gate D. anode or cathode

The technique of assigning a memory address to each I/O device in the computer system is called: A. memory-mapped I/O B. ported I/O C. dedicated I/O D. wired I/O

The temperature coefficient can be _____ for different Zener levels. A. positive B. negative C. zero D. all of the above

The term _____ is often used when comparing the resistance level of materials. A. permittivity B. inductivity C. conductivity D. resistivity

The term buffer/driver signifies the ability to provide low output currents to drive light loads. A. True B. False

The test current in a Zener diode IZT is the current defined by the _____ power level. A. 0.25 B. 0.5 C. 0.75 D. 1.00

The three terminals of the JFET are the _____, _____, and _____. A. gate, collector, emitter B. base, collector, emitter C. gate, drain, source D. gate, drain, emitter

The threshold voltage of a MOSFET can be lowered by 1. using thin gate oxide 2. reducing the substrate concentration 3. increasing the substrate concentration. Of the above statement A. 3 alone is correct B. 1 and 2 are correct C. 1 and 3 are correct D. 2 alone is correct

The time it takes for an input signal to pass through internal circuitry and generate the appropriate output effect is known as ________. A. fan-out B. propagation delay C. rise time D. fall time

The time needed for an output to change from the result of an input change is known as: A. noise immunity B. fan-out C. propagation delay D. rise time

The total number of input words for 4 input OR gate is A. 20 B. 16 C. 12 D. 8

The total number of leads in MOS controlled thyristor is A. 2 B. 3 C. 4 D. 2 or 3

The total number of leads in SUS, SBS and SCS respectively are A. 3, 3, 4, B. 3, 3, 3 C. 2, 3, 3 D. 3, 3, 5

The total number of leads in reverse conducting thyristor is A. 2 B. 3 C. 1 D. 4

The total time required for the transistor to switch from the "off" to the "on" state is designated as ton and defined as the delay time plus the time element. A. True B. False

The transfer curve can be obtained by ________. A. using Shockley's equation B. using both Shockley's equation and by output characteristics C. characteristics D. None of the above

The transfer curve is not defined by Shockley's equation for the _____. A. JFET B. depletion-type MOSFET C. enhancement-type MOSFET

The transfer curve is not defined by Shockley's equation for the ________. A. JFET B. depletion-type MOSFET C. enhancement-type MOSFET D. BJT

The two modes of operation of three phase bridge inverters are known as A. 60° mode and 120° mode B. 90° mode and 120° mode C. 120° mode and 180° mode D. 120° mode and 240° mode

The two-transistor model of a thyristor consists of two transistors : A. one n-p-n and other p-n-p B. both p-n-p C. both n-p-n D. one n-p-n and other UJT

The units for the HIGH time for a periodic wave are ________. A. seconds B. hertz C. cycles D. %

The units for transconductance are A. ohms B. amperes C. volts D. siemens

B The units of h11 are ohms and units of h22 siemens.

The units of transistor h parameters h11 and h22 are the same. A. True B. False

The use of free wheeling diode in controlled rectifier improves the waveshape of load current. A. True B. False

The value of 25 in octal system is A. 40 B. 20 C. 100 D. 200

B Value of C is proportional to maximum difference between reverse charge of SCRs in series.

The value of capacitor C for dynamic equalising circuit of series connected thyristors is determined by A. forward characteristics of thyristors B. reverse recovery characteristics of thyristors C. both forward and reverse recovery characteristics of thyristors D. none of the above

The value of parameter re used in re transistor model A. increases with increase in temperature B. decreases with increase in temperature C. is not affected by increase in temperature D. either (b) or (c)

The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage that will occur on the reverse biased diode will be A. 100 V B. 88 V C. 50 V D. 25 V

The waveshape of output voltage of half bridge inverter is A. sinusoidal B. square C. triangular D. either (a) or (b)

The word "interfacing" as applied to digital electronics usually means: A. a conditioning circuit connected between a standard TTL NAND gate and a standard TTL OR gate B. a circuit connected between the driver and load to condition a signal so that it is compatible with the load C. any gate that is a TTL operational amplifier designed to condition signals between NMOS transistors D. any TTL circuit that is an input buffer stage

The work function of a photo surface whose threshold wave length is 1200 A, will be A. 0.103 eV B. 0.673 eV C. 1.03 eV D. 1.27 eV

There is(are) ________ in the internal construction of a TO-92 package. A. gold bond wires B. a copper frame C. epoxy encapsulation D. All of the above

Thyristors are not suitable for logic circuits. A. True B. False

Thyristors can be used for control of A. dc separately excited motor B. dc shunt motor C. dc series motor D. all of the above

Thyristors connected in series need : A. static equalizing circuit B. dynamic equalizing circuit C. both static and dynamic equalizing circuits D. none of the above

To obtain a 50% duty cycle in an astable 555 timer circuit: A. tLO = tHI B. RA = RB and short RB with a diode during the capacitor charging cycle C. capacitor voltage must rise above 1/3 VCC D. tLO = tHI, RA = RB, and short RB with a diode during the capacitor charging cycle

To prevent a DC return between source and load, it is necessary to use A. resistor between source and load B. inductor between source and load C. capacitor between source and load D. either (a) or (b)

D current through inductance cannot change instantaneously.

To protect an SCR against high di/dt we connect A. a capacitance in series with SCR B. a capacitance in parallel with SCR C. an inductance in parallel with SCR D. an inductance in series with SCR

A Resistor reduces surge current.

To protect the diodes in a rectifier and capacitor input filter circuit it is necessary to use A. surge resistor B. surge inductor C. surge capacitor D. both (a) and (b)

To turn off an SCR, it is necessary to reduce its current to less than : A. trigger current B. holding current C. breakover current D. none of the above

Totem-pole outputs ________ be connected ________ because ________. A. can, in parallel, sometimes higher current is required B. cannot, together, if the outputs are in opposite states excessively high currents can damage one or both devices C. should, in series, certain applications may require higher output voltage D. can, together, together they can handle larger load currents and higher output voltages

Totem-pole outputs ________ be connected ________ because ________. A. can, in parallel, sometimes higher output current is required B. cannot, together, if the outputs are in opposite states excessively high currents can damage one or both of the devices C. should, in series, certain applications may require higher output voltage D. can, together, together they can handle larger load currents and higher output voltages

Transistors are _____-terminal devices. A. 2 B. 3 C. 4 D. 5

Triggering a retriggerable one shot during pulse generation will: A. time out the original pulse B. extend the pulse to this trigger width C. have no effect D. double the original pulse width

Two CE stages, 1 and 2 are coupled through a capacitor. VCC is the same for both. Base resistances RB1 and RB2 are such that RB1 > RB2. Then A. base currents for both stages are equal B. base current of stage 1 is more than that of stage 2 C. base current of stage 2 is more than that of stage 1 D. either (b) or (c)

Two thyristor of same rating and same specifications A. will have equal turn on and turn off periods B. will have equal turn on but unequal turn off periods C. may have equal or unequal turn on and turn off periods D. will have unequal turn on and turn off periods

Two thyristors of the same rating and specifications A. will have equal on state voltage drops B. will have equal forward blocking voltage for the same current C. will have different on state voltage drops D. may have equal or different on state voltage drops and equal or different forward blocking voltage's for the same current

Typical values of DI/DT(S/U SEC) AND DV/DT 9V/U SEC) for an SCR are in the range of A. 1 to 10 B. 25 to 500 C. 0.1 to 1 D. 1000 to 2000

Typical values of voltage amplification for the common-base configurations vary from ________ and the current gain is always ________ . A. less than 1, 50 to 300 B. 50 to 300, larger than 1 C. 50 to 300, less than 1 D. larger than 1, 50 to 300

UJT can be used for A. firing an SCR B. turning off an SCR C. both firing and turning off an SCR D. none of the above

A In a synchronous counter clock pulses are applied to all flip-flops simultaneously. Hence minimum time delay and high frequency.

Using the same flip flops A. a synchronous flip flop can operate at higher frequency than ripple counter B. a ripple counter can operate at higher frequency than synchronous counter C. both ripple and synchronous counter can operate at the same frequency D. can not determine

Using the schematic diagram of a TTL NAND gate, determine the state of each transistor (ON or OFF) when all inputs are high. A. Q1-ON, Q2-OFF, Q3-ON, Q4-OFF B. Q1-ON, Q2-ON, Q3-OFF, Q4-OFF C. Q1-OFF, Q2-OFF, Q3-ON, Q4-ON D. Q1-OFF, Q2-ON, Q3-OFF, Q4-ON

VMOS FETs have a ________ temperature coefficient that will combat the possibility of thermal runaway. A. positive B. negative C. zero D. None of the above

Varying the _____ can control the location of the Zener region. A. forward current B. doping levels C. forward voltage D. dc resistance

What are the major differences between the 5400 and 7400 series of ICs? A. The 5400 series are military grade and require tighter supply voltages and temperatures. B. The 5400 series are military grade and allow for a wider range of supply voltages and temperatures. C. The 7400 series are an improvement over the original 5400s. D. The 7400 series was originally developed by Texas Instruments. The 5400 series was brought out by National Semiconductors after TI's patents expired, as a second supply source.

What are the ranges of the ac input and output resistance for a common-base configuration? A. 10 -100 , 50 k -1 M B. 50 k -1 M, 10 -100 C. 10 -100 k, 50 -1 k D. None of the above

What are the ranges of the ac input and output resistance for a common-base configuration? A. 10-100Ω, 50 k-1 MΩ B. 50 k-1 MΩ, 10-100Ω C. 10-100 kΩ, 50 -1 kΩ D. none of the above

What can a relay provide between the triggering source and the output that semiconductor switching devices cannot? A. total isolation B. faster C. higher current rating D. total isolation and higher current rating

What causes low-power Schottky TTL to use less power than the 74XX series TTL? A. The Schottky-clamped transistor B. Nothing. The 74XX series uses less power. C. A larger value resistor D. Using NAND gates

What controls the output pulse width of a one shot? A. the clock frequency B. the width of the clock pulse C. an RL time constant D. an RC time constant

What do we call the manipulation of an analog signal in a digital domain? A. Analog-to-digital conversion B. Digital-to-analog conversion C. Digital signal processing D. Signal filtering

What does ECL stand for? A. It stands for electron-coupled logic; all of the devices used within the gates are N-type transistors. B. It stands for emitter-coupled logic; all of the inputs are coupled into the device through the emitters of the input transistors. C. It stands for emitter-coupled logic; all of the emitters of the input transistors are connected together and each transistor functions as an emitter follower. D. It stands for energy-coupled logic; the input energy is amplified by the input transistors and allows the device to deliver higher output currents.

What does a high resistance reading in both forward- and reverse-bias directions indicate? A. a good diode B. an open diode C. a shorted diode D. a defective ohmmeter

What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter? A. Faulty device B. Good device C. Bad ohmmeter D. None of the above

What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter? A. faulty device B. good device C. bad ohmmeter D. none of the above

What does the discharge transistor do in the 555 timer circuit? A. charge the external capacitor to stop the timing B. charge the external capacitor to start the timing over again C. discharge the external capacitor to stop the timing D. discharge the external capacitor to start the timing over again

What is (are) the component(s) of electrical characteristics on the specification sheets? A. on B. off C. small-signal characteristics D. all of the above

What is (are) the component(s) of most specification sheets provided by the manufacturer? A. maximum ratings B. thermal characteristics C. electrical characteristics D. all of the above

What is a disadvantage of CMOS in place of TTL? A. It switches slower. B. It uses less power. C. It is smaller. D. cost

What is another name for a bistable multivibrator? A. an on-off switch B. an oscillator C. a flip-flop

What is occurring when two or more sources of data attempt to use the same bus? A. Bus contention B. Direct memory access C. Bus interruption D. PPI

What is the advantage of using CMOS logic over TTL? A. It switches faster. B. It uses less power. C. It is larger. D. cost

What is the advantage of using low-power Schottky (LS) over standard TTL logic? A. more power dissipation B. less power dissipation C. cost is less D. cost is more

What is the advantage of using serial data transmission over parallel data transmission? A. It is slower. B. Only one pair of wires is required. C. More people use it. D. It is faster.

What is the correct sequence of the following step in the fabrication of a monolithic, Bipolar junction transistor? 1. Emitter diffusion 2. Base diffusion 3. Buried layer formation 4. E pi-layer formation Select the correct answer using the codes given below: A. 3, 4, 1, 2 B. 4, 3, 1, 2 C. 3, 4, 2, 1 D. 4, 3, 2, 1

What is the difference between a mnemonic code and machine code? A. There is no difference. B. Machine codes are in binary, mnemonic codes are in shorthand English. C. Machine codes are in shorthand English, mnemonic codes are in binary.

What is the difference between a retriggerable one shot and a nonretriggerable one shot? A. The nonretriggerable can only be triggered once. B. The retriggerable can be triggered many times. C. The output pulse can be stretched with a nonretriggerable. D. The output pulse can be stretched with a retriggerable.

What is the difference between an astable multivibrator and a monostable multivibrator? A. The astable is free running. B. The astable needs to be clocked. C. The monostable is free running. D. none of the above

What is the difference between setup time and hold time? A. Setup time occurs after the active clock edge, hold time occurs before the active clock edge. B. Setup time occurs before the active clock edge, hold time occurs after the active clock edge. C. Setup time and hold time both occur at the active clock edge.

What is the difference between the 54XX and 74XX series of TTL logic gates? A. 54XX is faster. B. 54XX is slower. C. 54XX has a wider power supply and expanded temperature range. D. 54XX has a narrower power supply and contracted temperature range.

What is the difference between the 74HC00 series and the 74HCT00 series of CMOS logic? A. The HCT series is faster. B. The HCT series is slower. C. The HCT series is input and output voltage compatible with TTL. D. The HCT series is not input and output voltage compatible with TTL.

D Since the duration of output waveform is less than 180°, output voltage is less than input voltage.

What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode? A. The duration of output waveform is less than 180° B. Output voltage is less than input voltage C. Output voltage is more than input voltage D. Both (a) and (b)

What is the function of the comparators in the 555 timer circuit? A. to compare the output voltages to the internal voltage divider B. to compare the input voltages to the internal voltage divider C. to compare the output voltages to the external voltage divider D. to compare the input voltages to the external voltage divider

What is the increase in switching speed between 74LS series TTL and 74HC/HCT (High-Speed CMOS)? A. 5 B. 10 C. 50 D. 100

What is the level of IG in an FET? A. Zero amperes B. Equal to ID C. Depends on VDS D. Undefined

What is the level of IG in an FET? A. zero amperes B. equal to ID C. depends on VDS D. undefined

What is the level of drain current ID for gate-to-source voltages VGS less than (more negative than) the pinch-off level? A. zero amperes B. IDSS C. Negative value D. Undefined

What is the level of drain current ID for gate-to-source voltages VGS less than (more negative than) the pinch-off level? A. zero amperes B. IDSS C. negative value D. undefined

What is the major advantage of ECL logic? A. very high speed B. wide range of operating voltage C. very low cost D. very high power

What is the maximum power rating for LEDs? A. 150 mW B. 500 mW C. 1 W D. 10 W

What is the most frequently encountered transistor configuration? A. Common-base B. Common-collector C. Common-emitter D. Emitter-collector

What is the most frequently encountered transistor configuration? A. common-base B. common-collector C. common-emitter

What is the peak inverse voltage across each diode in a voltage doubler? A. Vm B. 2Vm C. 0.5Vm D. 0.25Vm

What is the purpose of adding two Zener diodes to the MOSFET in the figure? A. to reduce the input impedance B. to protect the MOSFET for both polarities C. to increase the input impedance D. none of the above

What is the range of an FET's input impedance? A. 10 to 1 k B. 1 k to 10 k C. 50 k to 100 k D. 1 M to several hundred M

What is the range of an FET's input impedance? A. 10 to 1 kΩ B. 1 k to 10 kΩ C. 50 k to 100 kΩ D. 1 M to several hundred MΩ

What is the range of invalid TTL output voltage? A. 0.0-0.4 V B. 0.4-2.4 V C. 2.4-5.0 V D. 0.0-5.0 V

What is the range of the operating voltage level for LEDs? A. 5-12 mV B. 1.7-3.3 V C. 5-12 V D. 20-25 V

What is the ratio of ID / IDSS for VGS = 0.5 VP? A. 0.25 B. 0.5 C. 1 D. 0

What is the ratio of ID /IDSS for VGS = 0.5VP? A. 0.25 B. 0.5 C. 1 D. 0

What is the ratio of the total width to that of the center layer for a transistor? A. 1:15 B. 1:150 C. 15:1 D. 150:1

What is the resistor value of an ideal diode in the region of conduction? A. 0 B. 5 kΩ C. undefined D. infinity

What is the result of taking more samples during the quantization process? A. More errors in the analog-to-digital conversion B. More bit requirements C. More accurate signal representation D. More bit requirements and more accurate signal representation

What is the standard TTL noise margin? A. 5.0 V B. 0.0 V C. 0.8 V D. 0.4 V

What is the state of an ideal diode in the region of nonconduction? A. an open circuit B. a short circuit C. unpredictable D. undefined

What is the static charge that can be stored by your body as you walk across a carpet? A. 300 volts B. 3,000 volts C. 30,000 volts D. Over 30,000 volts

What is the value of the transition capacitor for a silicon diode when VD = 0? (Choose the best answer.) A. 1 pF B. 3 pF C. 5 pF D. 10 pF

What is unique about TTL devices such as the 74S00? A. The gate transistors are silicon (S), and the gates therefore have lower values of leakage current. B. The S denotes the fact that a single gate is present in the IC rather than the usual package of 2-6 gates. C. The S denotes a slow version of the device, which is a consequence of its higher power rating. D. The devices use Schottky transistors and diodes to prevent them from going into saturation; this results in faster turn on and turn off times, which translates into higher frequency operation.

What is unique about TTL devices such as the 74SXX? A. These devices use Schottky transistors and diodes to prevent them from going into saturation; this results in faster turn-on and turn-off times, which translates into higher frequency operation. B. The gate transistors are silicon (S), and the gates therefore have lower values of leakage current. C. The S denotes the fact that a single gate is present in the IC rather than the usual package of 2-6 gates. D. The S denotes a slow version of the device, which is a consequence of its higher power rating.

What is used to graphically show the time relationship between two or more digital waveforms? A. reference diagram B. timing diagram C. voltage curve D. load line

What is αdc equal to? A. IB / IE B. IC / IE C. IC / IB D. none of the above

What is βdc equal to? A. IB / IE B. IC / IE C. IC / IB D. none of the above

What kind of computer program is used to convert mnemonic code to machine code? A. debug B. assembler C. C++ D. Fortran

What must be done to interface CMOS to TTL? A. A dropping resistor must be used on the CMOS 12 V supply to reduce it to 5 V for the TTL. B. As long as the CMOS supply voltage is 5 V, they can be interfaced; however, the fan-out of the CMOS is limited to two TTL gates. C. A 5 V Zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates. D. The two series cannot be interfaced without the use of special interface buffers designed for that purpose, such as the open-collector buffers.

What must be done to interface TTL to CMOS? A. A dropping resistor must be used on the CMOS 12 V supply to reduce it to 5 V for the TTL. B. As long as the CMOS supply voltage is 5 V, they can be interfaced; however, the fan-out of the TTL is limited to five CMOS gates. C. A 5 V Zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates. D. A pull-up resistor must be used between the TTL output-CMOS input node and Vcc; the value of RP will depend on the number of CMOS gates connected to the node.

What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter? A. 100 to a few k, exceeding 100 k B. Exceeding 100 k, 100 to a few k C. Exceeding 100 k, exceeding 100 k D. 100 to a few k, 100 to a few k

What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter? A. 100 to a few kΩ, exceeding 100 kΩ B. exceeding 100 kΩ, 100 to a few kΩ C. exceeding 100 kΩ, exceeding 100 kΩ D. 100 to a few kΩ, 100 to a few kΩ

What should be done to unused inputs on TTL gates? A. They should be left disconnected so as not to produce a load on any of the other circuits and to minimize power loading on the voltage source. B. All unused gates should be connected together and tied to V through a 1 k resistor. C. All unused inputs should be connected to an unused output; this will ensure compatible loading on both the unused inputs and unused outputs. D. Unused AND and NAND inputs should be tied to VCC through a 1 k resistor; unused OR and NOR inputs should be grounded.

What should be done with unused inputs to a TTL NAND gate? A. let them float B. tie them LOW C. tie them HIGH

What type of circuit is used at the interface point of an input port? A. decoder B. latch C. tristate buffer D. none of the above

What type of circuit is used at the interface point of an output port? A. decoder B. latch C. tristate buffer D. none of the above

What unit is used to represent the level of a diode forward current IF? A. pA B. nA C. μA D. mA

What would be the output voltage of a 7814 voltage regulator? A. -14 V dc B. +14 V dc C. -8 V dc D. +8 V dc

When UJT is used for thyristor gate signal, the output of UJT is A. sine wave B. square wave C. saw tooth wave D. either (a) or (c)

When VGS = 0 on an N-channel MOSFET switch, there is no ________ between the source and the drain. A. voltage drop B. conductive channel C. capacitance D. inductance

When a UJT is used as a relaxation oscillator the current should be A. less than Ip B. more than Iv C. more than Ip but less than Iv D. negative

When a capacitor charges: A. the voltage across the plates rises exponentially B. the circuit current falls exponentially C. the capacitor charges to the source voltage in 5×RC seconds D. all of the above

When a dc chopper feeds an RLE load, the load current, during steady state operation A. remains constant B. varies between maximum and minimum values C. may remain constant or vary D. is constant if R is constant

When a diode is not conducting, its bias is A. forward B. zero C. reverse D. zero or reverse

B Inner shell electrons are tightly bound to the nucleus. Their energy levels cannot be affected by presence of other atoms.

When a large number of atoms are brought together to form a crystal A. the energy levels of inner shell electrons are affected appreciably by the presence of other neighbouring atoms. B. The energy levels of outer shell electrons are affected appreciably by the presence of other neighbouring atoms. C. the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms. D. none of the above.

When a p-n junction is forward biased A. the width of depletion layer increases B. the width of depletion layer decreases C. the majority carriers move away from the junction D. the current is very small

A Holes and electrons move away from junction and therefore resistance increases to a high value.

When a p-n junction is reverse biased A. holes and electrons move away from the junction B. holes and electrons move towards the junction C. holes move towards junction and electrons move away from junction D. holes move away from junction and electrons move towards junction

A The reason that collector current is nearly equal to emitter current.

When a p-n-p transistor is properly biased to operate in active region the holes from emitter. A. diffuse through base into collector region B. recombine with electrons in base C. recombine with electrons in emitter D. none of the above

When a power diode is conducting, the voltage drop across it is about A. I V B. 5 V C. 20 V D. 50 V

B Therefore, the resistance is very high.

When a reverse bias is applied to a p-n junction, the width of depletion layer. A. decreases B. increases C. remains the same D. may increase or decrease

When a single phase dual converter is operating in circulating current mode A. both converters are working as rectifiers simultaneously B. one converter is always working as rectifier and the other as inverter C. only one converter is working at one time D. both converters are either working as rectifiers or as inverters simultaneously

When a thyristor is conducting, the voltage drop across it A. is absolutely constant B. decreases with increase in load current C. increases slightly with increase in load current D. none of the above

When a thyristor is conducting, the voltage drop across it is about A. 1 V B. 10 V C. 100 V D. 0.1 V

A Since electrons are negatively charged they will flow towards positive terminal.

When a voltage is applied to a semiconductor crystal then the free electrons will flow. A. towards positive terminal B. towards negative terminal C. either towards positive terminal or negative terminal D. towards positive terminal for 1 μs and towards negative terminal for next 1 μs

When an IC has two rows of parallel connecting pins, the device is referred to as a: A. QFP B. DIP C. TSSOP D. CMOS

When an SCR is in forward blocking mode, the applied voltage A. appears across only one junction B. is equally shared by two junctions C. is equally shared by three junctions D. may appear across one or more junctions

When an SCR is reverse biased A. two junctions are reverse biased and one junction is forward biased. B. all the three junctions are reverse biased. C. one junction is reverse biased and two junctions are forward biased. D. any of the above depending on the magnitude of reverse bias.

When checking a transistor by ohmmeter, a relatively ________ resistance is displayed for a forward-biased junction and ________ resistance for a reverse-biased junction. A. low, very high B. low, low C. high, high D. high, very low

When is a level-shifter circuit needed in interfacing logic? A. A level shifter is always needed. B. A level shifter is never needed. C. when the supply voltages are the same D. when the supply voltages are different

B Transformer coupling increases efficiency.

When load is coupled to class A amplifier through transformer, efficiency decreases. A. True B. False

A Both holes and electrons move away from junction.

When p-n junction is reverse biased the holes in p material move towards the junction and electrons in n material move away from the junction. A. True B. False

When referring to instruction words, a mnemonic is: A. a short abbreviation for the operand address B. a short abbreviation for the operation to be performed C. a short abbreviation for the data word stored at the operand address D. shorthand for machine language

D A high signal causes distortion because v-i characteristics of BJT is non-linear.

When the ac base voltage in a CE amplifier circuit is too high, the ac emitter current is A. zero B. constant C. alternating D. distorted

B Since core is saturated, change of flux is small and inductance is low.

When the core of a saturable reactor is saturated, the inductance is high. A. True B. False

C i is plotted on y-axis and v on x-axis. When passing through origin current can be zero only.

When the i-v curve of a photodiode passes through origin the illumination is A. maximum B. minimum C. zero D. equal to rated value

When the inputs to a flip-flop are changing at the same time that the active trigger edge of the input clock is making its transition, this condition is called: A. racing B. toggling C. slave loading D. pulse timing

When the output of a standard TTL gate is HIGH, it can ________. A. sink 16 mA of current from the attached input gates B. source 400 uA of current to no more than 10 attached gates C. source 16 mA of current to no more than 10 attached gates D. sink a maximum of 400 uA from no more than 10 load gates

When the outputs of several open-collector TTL gates are connected together, the gate outputs ________. A. usually burn out B. produce more voltage C. are ANDed together D. produce more fan-out

When thyristors are connected in parallel, the current distribution may become non-uniform due to A. inductive effect of current carrying conductors B. capacitive effect of current carrying conductors C. both inductive and capacitive effects D. none of the above

C Thyristors in series do not share the voltage equally and require voltage derating. Thyristors in parallel need current derating.

When thyristors are connected in series and parallel, it may be necessary to have : A. current derating B. voltage derating C. both current and voltage derating D. none of the above

When was the first 8-bit microprocessor introduced? A. 1969 B. 1974 C. 1979 D. 1985

Whenever a totem-pole TTL output goes from LOW to HIGH, a high-amplitude current spike is drawn from the Vcc supply. How is this effect corrected to a digital circuit? A. By connecting a radio-frequency capacitor from Vcc to ground. B. By using a switching power supply C. By connecting a capacitor from Vout to ground D. By connecting a large resistor from Vcc to Vout

Which A/D conversion method has a fixed conversion time? A. Single-slope analog-to-digital converter B. Dual-slope analog-to-digital converter C. Digital-ramp analog-to-digital converter D. Successive-approximation analog-to-digital converter

Which bus is a bidirectional bus? A. address bus B. data bus C. address bus and data bus D. none of the above

Which bus is bidirectional? A. Address bus B. Control bus C. Data bus D. None of the above

Which capacitor appears in the forward-bias region? A. 4Ω B. 32Ω C. 40Ω D. 140Ω

Which capacitor appears in the forward-bias region? A. diffusion B. transition C. depletion D. none of the above

Which chopper circuit operates in all the 4 quadrants? A. A B. C C. D D. E

Which chopper circuit operates in quadrants 1 and 4? A. A B. B C. D D. E

Which chopper circuit uses saturable reactor? A. Auxiliary commutated B. Jones chopper C. Morgan chopper D. Load commutated

Which component of the collector current IC is called the leakage current? A. Majority B. Independent C. Minority D. None of the above

Which component of the collector current IC is called the leakage current? A. majority B. independent C. minority D. none of the above

Which device has one input and many outputs? A. Multiplexer B. Demultiplexer C. Counter D. Flip flop

Which device(s) have almost ideal ON and OFF resistances? A. electromechanical relays B. manual switches C. semiconductor devices (diodes and transistors) D. electromechanical relays and manual switches

Which diode(s) has (have) a zero level current and voltage drop in the ideal model? A. Si B. Ge C. both Si and Ge D. neither Si nor Ge

C It is similar to triode.

Which display device resembles vacuum tube? A. LED B. LCD C. VF D. None of these

Which equation is correct? A. VNL = VIL(max) + VOL(max) B. VNH = VOH(min) + VIH(min) C. VNL = VOH(min) - VIH(min) D. VNH = VOH(min) - VIH(min)

Which factor does not affect CMOS loading? A. Charging time associated with the output resistance of the driving gate B. Discharging time associated with the output resistance of the driving gate C. Output capacitance of the load gates D. Input capacitance of the load gates

Which family of devices has the characteristic of preventing saturation during operation? A. TTL B. MOS C. ECL D. IIL

Which inverter circuit uses coupled inductors? A. Modified McMurray full bridge inverter B. McMurray Bedford half bridge inverter C. Modified McMurray Bedford half bridge inverter D. Both (b) and (c)

Which is a typical application of digital signal processing? A. Noise elimination B. Music signal processing C. Image processing D. All of the above

Which is not a MOSFET terminal? A. Gate B. Drain C. Source D. Base

Which is not a precaution for handling CMOS? A. Devices should be placed with pins down on a grounded surface, such as a metal plate. B. All tools, test equipment, and metal workbenches should be earth grounded. C. CMOS devices should not be inserted into sockets or PC boards with the power on. D. Wear wool clothes at all times.

Which is not an A/D conversion error? A. Differential nonlinearity B. Missing code C. Incorrect code D. Offset

Which is not an operand? A. Variable B. Register C. Memory location D. Assembler

Which is not an output state for tristate logic? A. HIGH B. LOW C. High-Z D. Low-Z

Which is not part of emitter-coupled logic (ECL)? A. Differential amplifier B. Bias circuit C. Emitter-follower circuit D. Totem-pole circuit

Which is not part of the execution unit (EU)? A. Arithmetic logic unit (ALU) B. Clock C. General registers D. Flags

Which logic family combines the advantages of CMOS and TTL? A. BiCMOS B. TTL/CMOS C. ECL D. TTL/MOS

Which logic family is characterized by a multiemitter transistor on the input? A. ECL B. CMOS C. TTL D. None of the above

Which method bypasses the CPU for certain types of data transfer? A. Software interrupts B. Interrupt-driven I/O C. Polled I/O D. Direct memory access (DMA)

Which microprocessor has multiplexed data and address lines? A. 8086/8088 B. 80286 C. 80386 D. Pentium

Which mode of operation is being used when a 555 timer chip has two external resistors and an external capacitor? A. monostable B. pulse stretching C. Schmitt triggering D. astable

Which of following regions is (are) part of the output characteristics of a transistor? A. active B. cutoff C. saturation D. all of the above

Which of the following FETs has the lowest input impedance? A. JFET B. MOSFET depletion-type C. MOSFET enhancement-type D. None of the above

Which of the following FETs has the lowest input impedance? A. JFET B. MOSFET depletion-type C. MOSFET enhancement-type D. none of the above

Which of the following applies to MOSFETs? A. No direct electrical connection between the gate terminal and the channel B. Desirable high input impedance C. Uses metal for the gate, drain, and source connections D. All of the above

Which of the following applies to MOSFETs? A. no direct electrical connection between the gate terminal and the channel B. desirable high input impedance C. uses metal for the gate, drain, and source connections D. all of the above

Which of the following applies to a safe MOSFET handling? A. Always pick up the transistor by the casing. B. Power should always be off when network changes are made. C. Always touch ground before handling the device. D. All of the above

Which of the following applies to a safe MOSFET handling? A. always pick up the transistor by the casing B. power should always be off when network changes are made C. always touch ground before handling the device D. all of the above

Which of the following are included in the architecture of computer? 1. Addressing mode, design of CPU 2. Instruction set, data format 3. Secondary memory, operating system Select the correct answer using the codes given below: A. 1 and 2 B. 2 and 3 C. 1 and 3 D. 1, 2 and 3

Which of the following are the three basic sections of a microprocessor unit? A. operand, register, and arithmetic/logic unit (ALU) B. control and timing, register, and arithmetic/logic unit (ALU) C. control and timing, register, and memory D. arithmetic/logic unit (ALU), memory, and input/output

Which of the following best defines Nyquist frequency? A. The frequency of resonance for the filtering circuit B. The second harmonic C. The lower frequency limit of sampling D. The highest frequency component of a given analog signal

Which of the following buses is primarily used to carry signals that direct other ICs to find out what type of operation is being performed? A. data bus B. control bus C. address bus D. address decoder bus

Which of the following can be obtained from the last scale factor of a curve tracer? A. hFE B. alpha dc C. alpha ac D. beta ac

Which of the following can be obtained from the last scale factor of a curve tracer? A. hFE B. αdc C. αac D. βdc

Which of the following circuit parameters would be most likely to limit the maximum operating frequency of a flip-flop? A. setup and hold time B. clock pulse HIGH and LOW time C. propagation delay time D. clock transition time

Which of the following commutation methods is the overall circuit under damped? A. Class A B. Class B C. Class C D. Both class A and Class B

Which of the following configurations can a transistor set up? A. common-base B. common-emitter C. common-collector D. all of the above

Which of the following controls the level of ID? A. VGS B. VDS C. IG D. VDG

Which of the following currents is nearly equal to each other? A. IB and IC B. IE and IC C. IB and IE D. IB, IC, and IE

Which of the following devices can check the condition of a semiconductor diode? A. digital display meter (DDM) B. multimeter C. curve tracer D. all of the above

Which of the following devices exhibit negative resistance characteristics? A. UJT B. PUT C. Both UJT and PUT D. UJT, PUT and SBS

Which of the following devices has substrate? A. JFET B. Depletion Type MOSFET C. Enhancement type MOSFET D. Both (b) and (c)

Which of the following devices has two gates? A. SCR B. SCS C. SUS D. SBS

Which of the following elements is most frequently used for doping pure Ge or Si? A. boron B. gallium C. indium D. all of the above

Which of the following equipment can check the condition of a transistor? A. Current tracer B. Digital display meter (DDM) C. Ohmmeter (VOM) D. All of the above

Which of the following equipment can check the condition of a transistor? A. current tracer B. digital display meter (DDM) C. ohmmeter (VOM) D. all of the above

Which of the following finds application in pocket calculators? A. TTL B. CMOS C. ECL D. Both (a) and (c)

Which of the following flip-flop timing parameters indicates the time it takes a Q output to respond to a Cp input? A. ts, th B. tPHL, tPLH C. tw (L), tw (H) D. fmax

Which of the following has highest conductivity? A. Silver B. Aluminium C. Tungsten D. Platinum

Which of the following input impedances is not valid for a JFET? A. 1010 B. 109 C. 108 D. 1011

Which of the following is (are) a stability factor? A. S(ICO) B. S(VBE) C. S(β) D. all of the above

Which of the following is (are) an FET? A. n-channel B. p-channel C. p-n channel D. n-channel and p-channel

Which of the following is (are) assumed in the approximate analysis of a voltage divider circuit? A. IB is essentially zero amperes. B. R1 and R2 are considered to be series elements. C. βRE ≥ 10R2 D. all of the above

Which of the following is (are) related to an emitter-follower configuration? A. The input and output signals are in phase. B. The voltage gain is slightly less than 1. C. Output is drawn from the emitter terminal. D. all of the above

Which of the following is (are) the advantage(s) of VMOS over MOSFETs? A. Reduced channel resistance B. Higher current and power ratings C. Faster switching time D. All of the above

Which of the following is (are) the advantage(s) of VMOS over MOSFETs? A. reduced channel resistance B. higher current and power ratings C. faster switching time D. all of the above

Which of the following is (are) the application(s) of a transistor? A. amplification of signal B. switching and control C. computer logic circuitry D. all of the above

Which of the following is (are) the terminal(s) of a transistor? A. emitter B. base C. collector D. all of the above

Which of the following is NOT a characteristic of a retriggerable monostable multivibrator? A. It is a dual multivibrator. B. It has an active-HIGH reset, which terminates all timing functions. C. It has no internal timing resistor. D. none of the above

Which of the following is an atom composed of? A. electrons B. protons C. neutrons D. all of the above

C Hamming code is widely used for error correction.

Which of the following is error correcting code? A. EBCDIC B. Gray C. Hamming D. ASCII

C Since it is non-saturating, ECL has low propagation delay.

Which of the following is non-saturating? A. TTL B. CMOS C. ECL D. Both (a) and (b)

Which of the following is not a basic element within the microprocessor? A. Microcontroller B. Arithmetic logic unit (ALU) C. Register array D. Control unit

Which of the following is not a computer bus? A. Data bus B. Control bus C. Timer bus D. Address bus

Which of the following is not a computer functional block? A. Analog-to-digital converter B. Central-processing unit C. Memory D. Input/output ports

Which of the following is not a jump instruction? A. JB (jump back) B. JA (jump above) C. JO (jump if overflow) D. JMP (unconditional jump)

Which of the following is not an 8086/8088 general-purpose register? A. Code segment (CS) B. Data segment (DS) C. Stack segment (SS) D. Address segment (AS)

Which of the following is not an arithmetic instruction? A. INC (increment) B. CMP (compare) C. DEC (decrement) D. ROL (rotate left)

Which of the following is not an enhancement to the Pentium that was unavailable in the 8086/8088? A. "Pipelined" architecture B. Expansion of cache memory C. Inclusion of an internal math coprocessor D. Data/address line multiplexing

Which of the following is susceptible to race condition? A. R-S latch B. D latch C. Both R - S and D latches D. None of the above

C As wavelength decreases, frequency increases and maximum velocity of electron increases.

Which of the following is true as regards photo emission? A. Velocity of emitted electrons is dependent on light intensity B. Rate of photo emission is inversely proportional to light intensity C. Maximum velocity of electron increases with decreasing wave length D. Both holes and electrons are produced

Which of the following is used for generating time varying wave forms? A. MOSFET B. PIN diode C. Tunnel diode D. UJT

Which of the following logic families has the highest maximum clock frequency? A. S-TTL B. AS-TTL C. HS-TTL D. HCMOS

Which of the following logic families has the highest noise margin? A. TTL B. LS TTL C. CMOS D. HCMOS

Which of the following logic families has the shortest propagation delay? A. CMOS B. BiCMOS C. ECL D. 74SXX

Which of the following logic families has the shortest propagation delay? A. S-TTL B. AS-TTL C. HS-TTL D. HCMOS

C Only LC oscillators are suitable for MHz range.

Which of the following oscillators is suitable for frequencies in the range of mega hertz? A. RC phase shift B. Wien bridge C. Hartley D. Both (a) and (c)

Which of the following ratings appear(s) in the specification sheet for an FET? A. voltages between specific terminals B. current levels C. power dissipation D. all of the above

Which of the following ratings is true? A. Si diodes have higher PIV and narrower temperature ranges than Ge diodes. B. Si diodes have higher PIV and wider temperature ranges than Ge diodes. C. Si diodes have lower PIV and narrower temperature ranges than Ge diodes. D. Si diodes have lower PIV and wider temperature ranges than Ge diodes.

Which of the following represent(s) the cutoff region for an FET? A. ID = 0 mA B. VGS = VP C. IG = 0 D. All of the above

Which of the following represent(s) the cutoff region for an FET? A. ID = 0 mA B. VGS = VP C. IG = 0 D. all of the above

Which of the following statements apply to CMOS devices? A. The devices should not be inserted into circuits with the power on. B. All tools, test equipment, and metal workbenches should be tied to earth ground. C. The devices should be stored and shipped in antistatic tubes or conductive foam. D. All of the above.

Which of the following summarizes the important features of ECL? A. Low noise margin, low output voltage swing, negative voltage operation, fast, and high power consumption B. Good noise immunity, negative logic, high frequency capability, low power dissipation, and short propagation time C. Slow propagation time, high frequency response, low power consumption, and high output voltage swings D. Poor noise immunity, positive supply voltage operation, good low frequency operation, and low power

Which of the following summarizes the important features of emitter-coupled logic (ECL)? A. low noise margin, low output voltage swing, negative voltage operation, fast, and high power consumption B. good noise immunity, negative logic, high-frequency capability, low power dissipation, and short propagation time C. low propagation time, high-frequency response, low power consumption, and high output voltage swings D. poor noise immunity, positive supply voltage operation, good low-frequency operation, and low power

Which of the following transistor(s) has (have) depletion and enhancement types? A. BJT B. JFET C. MOSFET D. None of the above

Which of the following transistor(s) has (have) depletion and enhancement types? A. BJT B. JFET C. MOSFET D. none of the above

Which of the following voltages must have a negative level (value) in any npn biased circuit? A. VBE B. VCE C. VBC D. none of the above

Which of the following was not a design improvement for the 8086/8088 over the 8085? A. Execution unit (EU) B. 16-bit data bus C. Arithmetic logic unit (ALU) D. Bus interface unit (BIU)

Which of the following will not normally be found on a data sheet? A. Minimum HIGH level output voltage B. Maximum LOW level output voltage C. Minimum LOW level output voltage D. Maximum HIGH level input current

Which of the logic families listed below allows the highest operating frequency? A. 74AS B. ECL C. HCMOS D. 54S

Which of these are two state devices? A. Lamp B. Punched card C. Magnetic tape D. All of the above

Which of these commutation methods is used in AC-DC converters? A. Class A B. Class C C. Class D D. Class F

C Class C commutation uses an auxiliary SCR and it is also called auxiliary commutation.

Which of these commutation methods uses an auxiliary SCR? A. Class A B. Class B C. Class C D. Class D

Which of these commutation methods uses an external pulse for commutation? A. Class A B. Class C C. Class E D. Class F

Which of these commutation methods uses two leads? A. Class A B. Class B C. Class C D. Class D

Which of these devices can conduct in both directions? A. SCR B. SUS C. SBS D. UJT

B/D

Which of these devices have four layers? A. UJT B. SCR C. TRIAC D. SCR and TRIAC

Which of these has 3 layers? A. PIN diode B. Zener diode C. Schottky diode D. Photo diode

C Tunnel diode has heavily doped p and n layers called degenerate p and n materials.

Which of these has degenerate p and n materials? A. Zener diode B. PIN diode C. Tunnel diode D. Photo diode

B Tunnel diode has heavily doped p and n regions leading to very thin depletion layer.

Which of these has highly doped p and n region? A. PIN diode B. Tunnel diode C. Schottky diode D. Photodiode

Which of these triggering methods for series connected SCRs use LASCR in the gate circuit? A. Resistance triggering B. Simultaneous triggering C. Sequential triggering D. Optical triggering

Which power amplifier can deliver maximum load power? A. Class A B. Class AB C. Class B D. Class C

A Holes do not exist in conductors.

Which statement is false as regards holes A. Holes exist in conductors as well as semiconductors B. Holes constitute positive charges C. Holes exist only in semiconductors D. Holes and electrons recombine

Which term applies to the maintaining of a given signal level until the next sampling? A. Holding B. Aliasing C. Shannon frequency sampling D. "Stair-stepping"

Which transistor element is used in CMOS logic? A. FET B. MOSFET C. Bipolar D. Unijunction

Which type of ADC quantizes the analog signal into a stream of bits whose amount corresponds to the signal level? A. Successive approximation B. Sigma-delta C. Dual-slope D. None of the above

Which type of gate can be used to add two bits? A. Ex-OR B. Ex-NOR C. Ex-NAND D. NOR

Which type of programming is typically used for digital signal processors? A. Assembly language B. Machine language C. C D. None of the above

Why are the maximum value of VOL and the minimum value of VOH used to determine the noise margin rather than the typical values for these parameters? A. These are worst-case conditions. B. These are normal conditions. C. These are best-case conditions. D. It doesn't matter what values are used.

Why does the TTL family use a totem-pole circuit on the output? A. It provides active pull-up. B. It provides active pull-down. C. It provides active pull-up and active pull-down.

Why does the data sheet for the 7476 only give a minimum value for the clock pulse width (both HIGH and LOW)? A. nominal value B. best-case condition C. worst-case condition

Why is a decoupling capacitor needed for TTL ICs and where should it be connected? A. to block dc, connect to input pins B. to reduce noise, connect to input pins C. to reduce the effects of noise, connect between power supply and ground

Why is a pull-up resistor needed for an open collector gate? A. to provide Vcc for the IC B. to provide ground for the IC C. to provide the HIGH voltage D. to provide the LOW voltage

Why is a pull-up resistor needed when connecting TTL logic to CMOS logic? A. to increase the output LOW voltage B. to decrease the output LOW voltage C. to increase the output HIGH voltage D. to decrease the output HIGH voltage

Why is an exclusive-NOR gate also called an equality gate? A. The output is false if the inputs are equal. B. The output is true if the inputs are opposite. C. The output is true if the inputs are equal.

Why is parallel data transmission preferred over serial data transmission for most applications? A. It is much slower. B. It is cheaper. C. More people use it. D. It is much faster.

Why is the Schmitt trigger needed in the 60-Hz TTL-level clock pulse generator? A. to provide a triangle wave B. to provide a sine wave C. to provide a rounded pulse waveform D. to provide a sharp pulse waveform

Why is the fan-out of CMOS gates frequency dependent? A. Each CMOS input gate has a specific propagation time and this limits the number of different gates that can be connected to the output of a CMOS gate. B. When the frequency reaches the critical value, the gate will only be capable of delivering 70% of the normal output voltage and consequently the output power will be one-half of normal; this defines the upper operating frequency. C. The higher the number of gates attached to the output, the more frequently they will have to be serviced, thus reducing the frequency at which each will be serviced with an input signal. D. The input gates of the FETs are predominantly capacitive, and as the signal frequency increases the capacitive loading also increases, thereby limiting the number of loads that may be attached to the output of the driving gate.

Why is the operating frequency for CMOS devices critical for determining power dissipation? A. At low frequencies, power dissipation increases. B. At high frequencies, the gate will only be able to deliver 70.7 % of rated power. C. At high frequencies, charging and discharging the gate capacitance will draw a heavy current from the power supply and thus increase power dissipation. D. At high frequencies, the gate will only be able to deliver 70.7 % of rated power and charging and discharging the gate capacitance will draw a heavy current from the power supply and thus increase power dissipation.

Why must CMOS devices be handled with care? A. so they don't get dirty B. because they break easily C. because they can be damaged by static electricity discharge

Why should a LED be pulled LOW from a logic gate rather than pulled HIGH? A. LOW-level current is smaller. B. LOW-level current is larger. C. HIGH-level current is larger. D. LOW-level current is smaller and HIGH-level current is larger.

Why would a delay gate be needed for a digital circuit? A. A delay gate is never needed. B. to provide for setup times C. to provide for hold times D. to provide for setup times and hold times

Why, in most applications, are transistor switches used in place of relays? A. They consume less power. B. They are faster. C. They are quieter and smaller. D. all of the above

With interrupt-driven I/O, if two or more devices request service at the same time, ________. A. the device closest to the CPU gets priority B. the device that is fastest gets priority C. the device assigned the highest priority is serviced first D. the system is likely to crash

With most monostable multivibrators, what is the Q output when no input trigger has occurred? A. LOW B. +5 V C. SET D. HIGH

With surface-mount technology (SMT), the devices should: A. utilize transistor outline connections B. mount directly C. have parallel connecting pins D. require holes and pads

B Work function is the minimum energy required by the fastest electron at 0 K to escape from the metal surface.

Work function is the maximum energy required by the fastest electron at 0 K to escape from the metal surface. A. True B. False

A Therefore emission current from oxide coated cathode is more.

Work function of oxide coated cathode is much lower than that of tungsten cathode. A. True B. False

Voltage regulation is the principal application of the: junction diode light-emitting diode vacuum diode Zener diode

Zener diode

B Zero suppression is commonly used.

Zero suppression is not used in actual practice. A. True B. False

________ TTL allows three possible output states. A. Triswitch B. Triinput C. Tristate D. Trident

________ has high input impedance, fast switching speeds, and lower operating power levels. A. CMOS B. FET C. BJT D. None of the above

________ is about twice as fast as P-MOS. A. CMOS B. DMOS C. MOD D. N-MOS

________ is ideally suited for applications using battery power or battery backup power. A. MOS B. P-MOS C. N-MOS D. CMOS

________ output levels would not be a valid LOW for a TTL gate. A. 0.2 V B. 0.3 V C. 0.5 V D. All of the above.

A semi-conductor is described as a "general purpose audio NPN device". This would be: a bipolar transistor a silicon diode a triode an audio detector

a bipolar transistor

If a low level signal is placed at the input to a transistor, a higher level of signal is produced at the output lead. This effect is know as: detection modulation rectification amplification

amplification

The electrodes of a semi- conductor diode are known as: gate and source anode and cathode collector and base cathode and drain

anode and cathode

In a bipolar transistor, the _______ compares closest to the control grid of a triode vacuum tube. emitter base source collector

base

In a semi-conductor diode, electrons flow from: anode to cathode cathode to grid grid to anode cathode to anode

cathode to anode

In a bipolar transistor, the _______ compares closest to the plate of a triode vacuum tube. gate emitter collector base

collector

The three leads from a PNP transistor are named: drain, base and source collector, emitter and base collector, source and drain gate, source and drain

collector, emitter and base

One important application for diodes is recovering information from transmitted signals. This is referred to as: regeneration ionization biasing demodulation

demodulation

In a bipolar transistor, the _______ compares closest to the cathode of a triode vacuum tube. collector base drain emitter

emitter

A transistor can be destroyed in a circuit by: excessive heat excessive light saturation cut-off

excessive heat

In order for a diode to conduct, it must be: close coupled forward-biased enhanced reverse-biased

forward-biased

B It depends on intensity of incident light.

he amount of photoelectric emission current depends on the frequency of incident light. A. True B. False

he characteristics of which device has peak point and valley point A. SCR B. PUT C. SCS D. Shockley diode

n a 3 phase full converter, the firing angle is less than 60°. The instantaneous output voltage A. will have positive part only B. will have both positive and negative parts C. may have both positive and negative parts D. will have negative part if load is inductive

n a single phase semiconverter feeding a highly inductive load, the load current is A. sinusoidal B. nearly constant C. absolutely constant D. rectangular

B Each RC network gives 60° phase shift.

n an RC phase shift oscillator, the total phase shift of the three RC lead networks is A. 360° B. 180° C. 90° D. 0°

A Schottky transistors have low switching time and hence low propagation delay.

n digital circuits Schottky transistors are preferred over normal transistors because of their A. lower propagation delay B. lower power dissipation C. higher propagation delay D. higher power dissipation

n-type semiconductors A. are negatively charged B. are produced when indium is added as impurity to germanium C. are produced when phosphorus is added as impurity to silicon D. none of the above

The action of changing alternating current to direct current is called: amplification rectification transformation modulation

rectification

The primary purpose of a Zener diode is to: provide a voltage phase shift regulate or maintain a constant voltage to boost the power supply voltage provide a path through which current can flow

regulate or maintain a constant voltage

The basic semi-conductor amplifying device is the: tube P-N junction transistor diode

transistor

Zener diodes are used as: current regulators voltage regulators RF detectors AF detectors

voltage regulators

. An intrinsic silicon sample has 2 million free electrons. The number of holes in the sample is A. 2 million B. almost zero C. more than 2 million D. less than 2 million

. In a single phase full wave regulator feeding an R-L load, the power factor angle of load is θ. The range of control of firing angle a is A. 0 ≤ a ≤ p B. θ ≤ a ≤ p C. 0 ≤ a ≤ (p - θ) D. θ ≤ a ≤ (p + θ)

. Light dependent resistor is A. photo resistive device B. photo voltaic device C. photo emissive device D. either (a) or (c)

. Thyristors are suitable for dc circuit breakers but not for ac circuit breakers. A. True B. False

0.10112 = __________ . A. 0.687510 B. 0.680010 C. 0.010010 D. 0.500010

1's complement of 11100110 is A. 00011001 B. 10000001 C. 00011010 D. 00000000

2's complement of binary number 0101 is A. 1011 B. 1111 C. 1101 D. 1110

Bipolar transistors usually have: 2 leads 3 leads 1 lead 4 leads

3 leads

74 HC series can sink upto 4 mA. The 74 LS series has IIL(max) - 0.4 mA. How many 74 LS inputs be driven by 74 HC output? A. 100 B. none C. 8 D. 10

7BF16 = __________ 2 A. 0111 1011 1110 B. 0111 1011 1111 C. 0111 1011 0111 D. 0111 1011 0011

A varactor diode is A. reverse biased B. forward biased C. biased to breakdown D. unbiased

Assertion (A): A p-n junction is used as rectifier. Reason (R): A p-n junction has low resistance in forward direction and high resistance in reverse direction. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): Alkali metals are used as emitters in phototubes. Reason (R): Alkali metals have low work functions. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): In active region of CE output characteristics of BJT, collector current is nearly constant. Reason (R): Base current in CE connection is very small. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Assertion (A): The hybrid p model of a transistor can be reduced to h parameter model and vice versa. Reason (R): Hybrid p and h parameter models are interrelated as both of them describe the same device. A. Both A and R are true and R is correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

During induction heating of metals which of the following is abnormally high? A. Frequency B. Voltage C. Current D. Power factor

Fermi level in intrinsic semiconductor is at the centre of forbidden energy band. A. True B. False

Hall effect is observed in a specimen when it is carrying current and is placed in a magnetic field. The resulting electric field inside the speciment will be in A. direction normal to both current and magnetic field B. the direction of current C. direction antiparallel to magnetic field D. an arbitrary direction depend upon conductivity

In an ideal junction transistor the impurity concentration in emitter (E ), base (B) and collector (C) is such that A. E > B > C B. B > C > E C. C > E > B D. C = E = B

In intrinsic semiconductor magnitude of free electron and hole concentrations are equal. A. True B. False

The mean life time of carrier may range from 10-9 seconds to hundreds of μ-seconds. A. True B. False

When a p-n junction is forward biased, the current remains zero till the applied voltage overcomes the barrier potential. A. True B. False

Zener breakdown occurs A. due to rapture of covalent band B. mostly in germanium junctions C. in lightly doped junctions D. due to thermally generated minority carriers

A "floating" TTL input may be defined as: A. unused input that is tied to Vcc through a 1 k resistor. B. unused input that is tied to used inputs. C. unused input that is tied to the ground. D. unused input that is not connected.

A 0.01-uF capacitor is recommended by TTL manufacturers for ________ the power supply. A. decoupling B. filtering C. rectifying D. grounding

A LSB = (10.24 * 1000) / (2^10) c = (LSB/2) / 25

A 10 bit ADC with a full scale output voltage of 10.24 V is to be designed to have ± LSB/2 accuracy. If ADC is calibrated at 25°C, the maximum net temperature coefficient of ADC should not exceed A. ± 200 μV/°C B. ± 400 μV/°C C. ± 600 μV/°C D. ± 800 μV/°C

A 12 bit ADC is used to convert analog voltage of 0 to 10 V into digital. The resolution is A. 2.44 mV B. 24.4 mV C. 1.2 V D. none of the above

A 20-bit address bus can locate ________. A. 1,048,576 locations B. 2,097,152 locations C. 4,194,304 locations D. 8,388,608 locations

A 3 bit up-down counter can count from A. 000 to 111 B. 111 to 000 C. 000 to 111 and also from 111 to 000 D. none of the above

A 3 input NAND gate is to be used as inverter. Which of the following will give better results? A. The two unused inputs are left open B. The two unused inputs are connected to 0 C. The two unused inputs are connected to 1 D. None of the above

B Two thyristors for each phase.

A 3 phase ac regulator uses A. 3 thyristors B. 6 thyristors C. 9 thyristors D. 12 thyristors

B Two resistances are in series at any time.

A 3 phase bridge inverter is fed by 400 V battery. The load is star connected and has a resistance of 10 Ω per phase. The peak value of load current is A. 40 A B. 20 A C. 10 A D. 5 A

A 3 phase bridge inverter is fed by 400 V battery. The load is star connected and has a resistance of 10 Ω per phase. The peak value of thyristor current is A. 400/10 B. 400/15 C. 400/20 D. 400/30

A 3 phase dual converter consists of A. two 3 phase semiconverters connected in parallel B. two 3 phase semiconverters connected in antiparallel C. two 3 phase full converters connected in antiparallel D. two 3 phase full converters connected in parallel

A 3 phase fully controlled converter is a A. 3 pulse converter B. 6 pulse converter C. 2 pulse converter D. 12 pulse converter

B In this case synchronous speed at 50 Hz is 1500 rpm. Therefore synchronous speed at 25 Hz is 750 rpm. Since slip is about 3 - 5%, speed is about 720 rpm.

A 3 phase induction motor is controlled by voltage and frequency control such that the ratio V/f is constant. At 50 Hz, the speed is 1440 rpm. At 25 Hz, the speed is likely to be A. about 1350 rpm B. about 720 rpm C. about 360 rpm D. either (b) or (c)

A 3 phase induction motor is controlled by voltage and frequency control such that the ratio V/f is constant. At 50 Hz, the starting torque is 100 N-m. At 25 Hz, the starting torque A. will be less than 100 N-m B. will be more than 100 N-m C. may be more or less than 100 N-m depending on motor parameters D. very small

B If load torque is constant, the change in speed is very small.

A 3 phase induction motor is fed by a 3 phase ac regulator to change the stator voltage. The variation in speed will be more if A. load torque is constant B. load torque increases with increase in speed C. load torque decreases with increase in speed D. either (a) or (b)

A 3 phase semiconverter when supplying a certain load has a rectification efficiency of 0.6 and transformer utilisation factor of 0.35. When a 3 phase full converter is supplying the same load A. rectification efficiency will be more than 0.6 and TUF will be more than 0.35 B. rectification efficiency will be more than 0.6 but TUF will be less than 0.35 C. rectification efficiency will be less than 0.6 and TUF will be less than 0.35 D. rectification efficiency will be less than 0.6 but TUF will be more than 0.35

A 3 phase series inverter has A. 12 thyristors B. 6 thyristors C. 3 thyristors D. 3 or 6 thyristors

B The starting count depends on modulus. 4 bit decade down counter starts counting from 1010.

A 4 bit down counter starts counting from 1111 irrespective of modulus. A. True B. False

A 4 bit parallel type A/D converter uses a 6 volt reference. How many comparators are required and what is the resolution in volts? A. 0.375 V B. 15 V C. 4.5 V D. 10 V

D All the switches have to be closed so that the circuit can be made. In AND gate all the inputs have to be high for output to be high.

A 4 input AND gate is equivalent to A. 4 switches in parallel B. 2 switches in series and 2 in parallel C. three switches in parallel and one in series D. 4 switches in series

A 4-bit R/2R ladder digital-to-analog converter uses ________. A. one resistor value B. two resistor values C. three resistor values D. four resistor values

A BJT is a _____-controlled device. The JFET is a _____ - controlled device. A. voltage, voltage B. voltage, current C. current, voltage D. current, current

A BJT is a ________-controlled device. The JFET is a ________ - controlled device. A. voltage, voltage B. voltage, current C. current, voltage D. current, current

A CB amplifier has a = 0.98 and RL = 600 Ω. If IE = 3.5 mA, the current gain is A. 1 B. 0.98 C. 0.98 x 3.5 D. 3.5/0.98

C Input impedance of CE amplifier is β re = 100 X 6 = 600 Ω.

A CE amplifier has re = 6 Ω, β = 100 and a = 0.98. The input impedance is A. 6 Ω B. 100 Ω C. 600 Ω D. 98 Ω

B They are designated as T1 and T2 because diac can conduct in both directions.

A DIAC has two terminals, anode and cathode. A. True B. False

A Hartley oscillator is used for A. very low frequencies B. radio frequencies C. micro wave frequencies D. audio frequency

A LASCR has A. 4 semiconductor layers and 3 junctions B. 3 semiconductor layers and 2 junctions C. 2 semiconductor layers and 2 junctions D. any of these depending on the rating

A NAND gate has 3 inputs and one output. The number of thyristors required for this gate are A. 1 B. 2 C. 3 D. 3 or 4

A NAND gate has: A. active-LOW inputs and an active-HIGH output. B. active-LOW inputs and an active-LOW output. C. active-HIGH inputs and an active-HIGH output. D. active-HIGH inputs and an active-LOW output.

Which component can amplify a small signal using low voltages? A variable resistor An electrolytic capacitor A multiple-cell battery A PNP transistor

A PNP transistor

A Schmitt trigger has VT+ = 2.0 V and VT- = 1.2 V. What is the hysteresis voltage of the Schmitt trigger? A. 0.4 volt B. 0.6 volt C. 0.8 volt D. 1.2 volts

A Schmitt trigger: A. has two trip points B. is a zero crossing detector C. has positive feedback D. has two trip points and positive feedback

A Schottky diode clamp is used along with switching BJT for A. reducing the power dissipation B. reducing the switching time C. increasing the value of β D. reducing the base current

B It is a four layered PNPN device without a gate terminal. Its characteristics is similar to that of SCR with zero gate current. It is acting as a trigger switch for Thyristor.

A Shockley diode can be used A. in place of SCR B. as a trigger switch for SCR C. in place of UJT D. both in place of SCR and as a trigger switch for SCR

A Si sample is doped with a fixed number of group N impurities. The electron density n is measured from 4 K to 1200 k for the sample. Which one of the following is correct? A. n remains constant over the temperature range B. n increases monotonicaliy with increasing temp C. n increases first remains constant over a range and again increases with increasing temperature D. n increases show a peak and then decrease with temperature

A TRIAC can be turned on : A. by applying a positive signal to gate B. by applying a negative signal to gate C. by applying either positive or negative signal to gate D. none of the above

A TRIAC is equivalent to A. two thyristors in series B. two thyristors in parallel C. one thyristor and one diode D. one thyristor and one transistor

A TTL NAND gate with IIH(max) of 40 A per input drives ten TTL inputs. How much current does the drive output source? A. 40 uA B. 200 uA C. 400 uA D. 800 uA

A TTL NAND gate with IIL(max) of -1.6 mA per input drives eight TTL inputs. How much current does the drive output sink? A. -12.8 mA B. -8 mA C. -1.6 mA D. -25.6 mA

A TTL totem-pole circuit is designed so that the output transistors: A. are always on together B. provide linear phase splitting C. provide voltage regulation D. are never on together

A TTL totem-pole circuit is designed so that the output transistors: A. are always on together B. provide phase splitting C. provide voltage regulation D. are never on together

A UJT exhibits negative resistance characteristics when A. Current is less than valley current B. Current is less than peak current C. Current is more than peak current but less than valley current D. None of the above

C The applied bias governs the width of depletion layer. Therefore, capacitance varies with bias.

A Varactor diode has A. a fixed capacitance B. a fixed inductance C. a voltage variable capacitance D. a current variable inductance

A ________ is a testing and troubleshooting tool that generates a short-duration pulse when manually activated, usually by depressing a push button. A. cattle prod B. jimmy rod C. logic pulser D. bilateral switch

A binary-weighted-input digital-to-analog converter has a feedback resistor, Rf, of 12 k. If 50 uA of current is through the resistor, voltage out of the circuit is ________. A. 0.6 V B. -0.6 V C. 0.1 V D. -0.1 V

A binary-weighted-input digital-to-analog converter has an input resistor of 100 k. If the resistor is connected to a 5 V source, current through the resistor is ________. A. 50 mA B. 50 uA C. 5 mA D. 500 uA

A bridge type single phase cycloconverter changes the frequency f to f/3. Then one half wave of output contains A. 3 full waves of input B. 3 half waves of input C. 6 full waves of input D. 6 half waves of input

B In look ahead carry adder the carry is directly derived from the gates when original inputs are being added. Hence the addition is fast. This process requires more gates and is costly.

A carry look ahead adder is frequently used for addition because A. it costs less B. it is faster C. it is more accurate D. is uses fewer gates

A certain gate draws 1.8 A when its output is HIGH and 3.3 µA when its output is LOW. VCC is 5 V and the gate is operated on a 50% duty cycle. What is the average power dissipation (PD)? A. 2.55 uW B. 1.27 uW C. 12.75 uW D. 5 uW

A chopper A. converts constant voltage dc into ac and then into variable voltage dc B. converts constant voltage dc into variable voltage dc directly C. converts ac of one frequency into ac of another frequency D. converts ac to dc

A chopper cannot be line commutated. A. True B. False

C Efficiency is 50%. Therefore input is 20 W.

A class A transformer coupled power amplifier is to deliver 10 W output. The power rating of transistor should not be less than A. 5 W B. 10 W C. 20 W D. 40 W

A class D chopper A. can operate in first quadrant only B. can operate in second quadrant only C. can operate in either first or fourth quadrant D. can operate in all the quadrants

A counter type A/D converter contains a 4 bit binary ladder and a counter driven by a 2 MHz clock. Then conversion time A. 8 μ sec B. 10 μ sec C. 2 μ sec D. 5 μ sec

A crowbar circuit is generally needed for protection under fault conditions. A. True B. False

A crystal demonstrates the ________ effect when a mechanical force across the crystal causes a small voltage to be generated. A. photoelectric B. Co-pitts C. piezoelectric D. flywheel

A current source inverter has simple commutation circuit. A. True B. False

B The indicator of current tracer glows when its tip is held over a pulsating current path.

A current tracer responds to A. steady current only B. pulsating current only C. both pulsating and steady current D. none of the above

A cycloconverter can be A. step down B. step up C. step down or step up D. none of the above

A cycloconverter for single phase operation has A. one positive group and one negative group converters B. two positive group and two negative group converters C. three positive group and three negative group converters D. any of the above

A cycloconverter is a group of controlled rectifiers. A. True B. False

A cycloconverter uses A. natural commutation B. forced commutation C. either natural or forced commutation D. both natural and forced commutation together

A dc chopper is feeding an RLE load. The condition for maximum ripple is A. a = 1 B. a = 0.8 C. a = 0.5 D. a < 0.5

A dc chopper is feeding an RLE load. The current can become discontinuous if A. R/L is high B. a is low C. E is high D. none of the above

B Natural commutation is possible only in ac circuits.

A dc circuit breaker must use A. natural commutation B. forced commutation C. both natural and forced commutation D. either natural or forced commutation

A Average output voltage is reduced to 50% if a = 90°. Hence speed is also reduced to 50%.

A dc separately excited motor has a constant field current. The armature is fed from a single phase supply through a semi-converter. When a = 0, speed is 600 rpm. If a = 90°, the speed is likely to be A. about 300 rpm B. about 150 rpm C. about 75 rpm D. about zero

A dc series motor is coupled to a load whose torque is proportional to speed. It is fed by a single phase ac supply through a full converter. When speed is 500 rpm, firing angle is 45°. It is desired to raise the speed. It will be necessary to A. decrease the firing angle B. increase the firing angle C. either decrease or increase the firing angle depending on the required speed D. decrease the load torque

C A decade counter counts from 0 to 9. It has 4 flip-flops. The states skipped are 10 to 15 or 1010 to 1111.

A decade counter skips A. binary states 1000 to 1111 B. binary states 0000 to 0011 C. binary states 1010 to 1111 D. binary states 1111 to higher

A device which converts BCD to seven segment is called A. encoder B. decoder C. multiplexer D. none of these

A diode is in the "_____ " state if the current established by the applied sources is such that its direction matches that of the arrow in the diode symbol, and VD 0.7 V for Si and VD 0.3 V for Ge. A. off B. on C. neutral D. quiescent

A diode placed in parallel across a relay coil serves what function? A. to regulate input voltage B. to protect the coil from arcing C. to ensure most of the current passes through the coil D. to reduce arcing across the relay contacts

C Modulus 13 x modulus 6 = modulus 78.

A divide by 78 counter can be obtained by A. 6 numbers of mod-13 counters B. 13 numbers of mod-6 counters C. one mod-13 counter followed by mod-6 counter D. 13 number of mod-13 counters

A dynamic RAM cell which holds 5 V has to be refreshed every 20 ms so that the stored voltage does not fall by more than 0.5 V. If the cell has a constant discharge current of 0.1 pA, the storage capacitance of cell is A. 4 x 10-6 F B. 4 x 10-9 F C. 4 x 10-12 F D. 4 x 10-15 F

A forward voltage of 9 V is applied to a diode in series with a 1 kΩ load resistor. The voltage across load resistor is zero. It indicates that A. diode is short circuited B. diode is open circuited C. resistor is open circuited D. diode is either short circuited or open circuited

A full adder can be made out of A. two half adders B. two half adders and a OR gate C. two half adders and a NOT gate D. three half adders

A full bridge inverter is fed by a battery of 30 V. The rms value of output voltage is A. 15 V B. 15SQRT2 V C. 30 V D. 30SQRT2 V

A Since two diodes are in series bridge rectifier, voltage drop is more.

A full wave rectifier using centre tapped transformer and a bridge rectifier use similar diodes and have equal no load output voltage. Under equal load conditions A. Output voltage of bridge rectifier B. Output voltage of bridge rectifier will be more than that of other C. Output voltage of both will be exactly equal D. Output voltage of any one may be more than that of other

A fully controlled bridge converter can operate in quadrants A. 1 B. 1 and 2 C. 1 and 3 D. 1 and 4

A fully controlled bridge converter feeds a highly inductive load such that the load current can be assumed to be constant. The wave shape of input current is A. dc B. sinusoidal C. rectangular D. none of the above

A fully controlled bridge converter is feeding an RLE load. For some circuit conditions firing angle is 47°. If connections of battery are reversed, the firing angle is likely to be A. 47° B. less than 47° C. more than 47° D. either more or less than 47°

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