ELEX PB 03
A comparison between ring and Johnson counters indicates that: a Johnson counter has more flip-flops but less decoding circuitry a Johnson counter has an inverted feedback path a ring counter has an inverted feedback path a ring counter has fewer flip-flops but requires more decoding circuitry
a Johnson counter has an inverted feedback path
The typical range of β for a Darlington amplifier is in the range of a very small value in the range 4 to 40 a much higher value in the range of 4000 to about 40,000 a slightly higher value in the range 400 to 4000 a moderate value in the range of 40 to 400
a much higher value in the range of 4000 to about 40,000
When a BJT is operating in the saturation region the voltage drop from the collector to the emitter V_CE is approximately equal to: equal to the emitter voltage almost equal to zero (about 0.3 V) collector current times the collector resistor collector supply voltage
almost equal to zero (about 0.3 V)
Which of the figures shown below represents the exclusive-NOR gate? d a c b
b
The positive feedback circuit in a Wien-bridge oscillator is used to: bias the negative feedback network determine the frequency of operation prevent unwanted oscillations control the gain of the circuit
control the gain of the circuit
For the circuit shown below, find i(t). 2 sin (2t + 5.77°) A cos (2t - 84.23°) A cos (2t + 84.23°) A 2 sin (2t - 5.77°) A
cos (2t - 84.23°) A
The ideal voltage regulator maintains a constant dc output voltage regardless of changes in: its input voltage its load current demand either its load current demand or its input voltage its output voltage demand
either its load current demand or its input voltage
In case of the two-transistor model (T1 & T2) of GTO with anode-short, the anode-short is placed between the: emitter of T1 & base of T1 emitter of T1 & collector of T2 emitter of T1 & base of T2 emitter of T1 & T2
emitter of T1 & base of T1
The feedback amplifier is unstable if the Nyquist curve plotted ________the (-1+ j0) point and it is stable otherwise. passes right over does not come close to passes to the left of encloses (encircles)
encloses (encircles)
A high pass active filter connection using an operational amplifier will provide a constant output for all frequencies higher than f_ol from dc to infinite frequency from dc to f_oh from f_ol to f_oh
for all frequencies higher than f_ol
The Cascade connection arrangement is designed to provide high input impedance with low voltage gain to ensure that the Miller capacitance is at a minimum with CB stage so that the amplifier provides good operation in the _______frequency range. mid range low entire frequency range high
high
Voltage-series feedback _________the bandwidth of an op-amp. reduces by half decreases increases has no affect on
increases
Synchronous counters eliminate the delay problems encountered with asynchronous (ripple) counters because the: input clock pulses are applied only to the first and last stages input clock pulses are not used to activate any of the counter stages input clock pulses are applied simultaneously to each stage input clock pulses are applied only to the last stage
input clock pulses are applied simultaneously to each stage
For the following circuit shown below, the SCR (THY2) is: forced commutated at ωt = π naturally commutated at ωt = π naturally commutated at ωt = 2π forced commutated at ωt = 2π
naturally commutated at ωt = π
In designing Algorithmic State Machine (ASM) with multiplexers, the registers hold: output input present binary state next binary state
present binary state
CPU fetches the instruction from memory according to the value of ____________. instruction register program counter status register program status word
program counter
Each programmable array logic (PAL) gate product is applied to an OR gate and, if combinational logic is desired, the product is ORed and then: sent to an inverter for output sent immediately to an output pin the polarity fuse is restored passed to the AND function for output
sent to an inverter for output
If one silicon diode and one germanium diode are connected in series, the voltage drop across the combination of the two diodes will be equal to the forward drop equal to that of the: difference of the voltage drops across the two diodes silicon diode germanium diode sum of the voltage drops across the two diodes
sum of the voltage drops across the two diodes
Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be: 0.04 0.001 0.0001 0.08
0.001
Twelve identical wires of resistance 6 ohms each are arranged to form the edge of a cube. A current of 40 mA is led into the cube at one corner and out at the other diagonally opposite corner. Calculate the potential difference developed between these corners. 0.20 V 0.28 V 0.22 V 0.24 V
0.20 V
What is the minimum separation required between security wiring and AC power wiring when they are installed in parallel wire runs? 18 inches 12 inches 6 inches 2 feet
12 inches
The collector voltage of a Class B push pull amplifier with Vcc = 40 Volts swings down to a minimum of 4 volts. The total power dissipation in both the transistors is 36 watts. Compute the total dc power input of the amplifier. 182.25 W 152.85 W 125.58 W 122.85 W
122.85 W
A BJT has a base current of 250 µA and emitter current of 15mA. Determine the collector current gain and β. 15.17 mA, 59 14.75 mA, 59 15.74 mA, 69 17.45 mA, 49
14.75 mA, 59
Design a series voltage regulator to supply 1A to a load at a constant voltage of 9 V. The supply voltage to regulator is 15 V±10%. The minimum zener current is 12 mA. For the transistor to be used, assume V_BE = 0.6 V and β = 50. 176.85 ohms 186.75 ohms 168.75 ohms 157.68 ohms
168.75 ohms
A coil and capacitor are in series. The inductance is 88 mH and the capacitance is 1000 pF. What is the resonant frequency? 17 MHz 17 kHz 540 Hz 540 kHz
17 kHz
The ohmic resistance of a large magnetic contactor is measured to be 20 ohms. A 230 V is impressed on the contactor and the current is taken as 3.2 A. Neglecting core loss, determine the inductance of the contactor in mH? 183 261 315 251
183
A three terminal voltage regulator drops out of regulation if the difference between the input voltage and the expected regulated output voltage is less than: 2.0 V The input and the expected output voltage can be exactly same. 90% of the expected regulated output voltage 10% of the expected regulated output voltage
2.0 V
For the circuit shown below, find i(t). 2.48 cos(300t - 68.2) A 2.48 cos(300t + 68.2) A 20 cos (300t + 68.2) A 20 cos(300t - 68.2) A
2.48 cos(300t - 68.2) A
The capacitance values of the two capacitors C₁ and C₂ of the resonant circuit of a Colpitts oscillator are C₁ = 20 nF and C₂ = 70 nF. The inductor has a value of 22 μH. What is the operating frequency of oscillator? 275.03 kHz 272.02 kHz 270.09 kHz 277.05 kHz
272.02 kHz
Find the Thevenin's resistance across the terminal AB for the following circuit shown below. 4.34 Ω 3.43 Ω 3.67 Ω 2.32 Ω
3.67 Ω
A differential amplifier has an open-loop voltage gain of 150 and a common input signal of 4.0 V to both terminals. An output signal of 15 mV results. Determine the common-mode gain and the CMRR. 3.75x10¯³ ; 82.04 dB 3.75x10¯³ ; 92.04 dB 3.75x10¯³ ; 72.04 dB 1.75x10¯³ ; 92.04 dB
3.75x10¯³ ; 92.04 dB
The reactance offered by a capacitor to alternating current of frequency 50 Hz is 10 ohms. If frequency is increased to 100 Hz, reactance becomes ____ ohm. 5 2.5 20 40
5
Obtain the source current I and the total power delivered to the circuit shown: 6.0 A, 329 W 4.0 A, 228 W 6.0 A, 228 W 4.0 A, 229 W
6.0 A, 228 W
The transconductance of a FET used in an amplifier circuit is 4000 µS. The load resistance is 15 kΩ and drain circuit resistance is 10 MΩ. Calculate the voltage gain of the amplifier circuit. 55 60 65 50
60
For the circuit shown below, what is the voltage across the inductor at t = 0? 0 V 58 V 60 V 20 V
60 V
Find the value of V1 and V2. 56.32 V; 78, 87 V 23.32 V; 46.45 V 64.28 V; 16.42 V 87.23 V; 29.23 V
64.28 V; 16.42 V
A current of 5 A is passed through a 1000-turn coil wound on a circular magnetic circuit of radius 120 mm. Calculate the magnetic field strength 6316 A/m 6361 A/m 6136 A/m 6631 A/m
6631 A/m
I₁ is the current flowing in the first mesh. I₂ is the current flowing in the second mesh and I₃ is the current flowing in the top mesh. If all three currents are flowing in the clockwise direction, find the value of I₁, I₂ and I₃. 7.67 A; 8.67A; 2 A 3.67 A; 6.67 A; 2 A 10.67 A; 7.67 A; 2 A 7.67 A; 10.67 A; 2 A
7.67 A; 10.67 A; 2 A
Part of a magnetic circuit is made from steel of length 120 mm, cross-sectional area 15 cm2 and relative permeability 800. Calculate its reluctance 75980 A/Wb 78590 A/Wb 70858 A/Wb 79580 A/Wb
79580 A/Wb
Assertion (A): A linear, negative feedback control system is invariable stable if its open loop configuration is stable. Reason (R): The negative feedback reduces the overall gain of the feedback. A is False and R is true A is True and R is false Both A and R are true and R is not correct Explanation of A Both A and R are true and R is correct explanation of A
A is False and R is true
Each impedance R + jX_L: All of the choices Corresponds to a unique inductance reactance. Corresponds to a unique point in the RL plane. Corresponds to a unique resistance.
All of the choices
In assembly language programming, a single two pass assembler does which of the following in the first pass? Builds the symbol table for the symbols and their values. All of the choices Allocates space for the literals. Computes the total length of the program.
All of the choices
Tellegen's theorem is valid for what network? All of the choices Passive or active Linear or non-linear Time variant or time invariant
All of the choices
Which of the following is an advantage of using dB representations of gain values? All of the choices Using dB values, we can represent large gain values with relatively small numbers. Positive and negative dB values represent gain and loss values that are reciprocals of each other. In multistage amplifiers, gain calculations are simplified by the use of dB values.
All of the choices
Which of the following pins of a microcontroller are directly connected with 8255? WR D0-D7 All of the choices RD
All of the choices
In a small signal transistor, what is the typical range of the parameter α? Greater than 1 Almost equal to 1 but always less than 1 (0.9 to 1.0) Between 0 and 1 Almost equal to 1 but always greater than 1 (1.0 to 1.1)
Almost equal to 1 but always less than 1 (0.9 to 1.0)
The surface integral of which parameter is zero? E H D B
B
If several identical stages of amplifiers; each having the exact same upper and lower cutoff frequencies; are connected in cascade, then the bandwidth of the resulting amplifier will: Be decreased Be increased Be equal to the sum of all the individual bandwidths Remain unchanged
Be decreased
A process is moved to wait queue when I/O request is made with: Blocking I/O Non-blocking I/O Asynchronous I/O Synchronous I/O
Blocking I/O
Nodal analysis can be applied for: Both planar and non-planar networks Neither planar nor non-planar networks Non-planar networks Planar networks
Both planar and non-planar networks
How do passive transducers develop electrical signals? By using internal source. By using a transformer. By using external source. By using a diode.
By using external source.
In the UJT firing circuit, the pulses are generated while the: There is no capacitor in a UJT firing circuit. Capacitor charges. Capacitor discharges. Capacitor voltage is zero.
Capacitor discharges.
Which Boolean algebra property allows us to group operands in an expression in any order without affecting the results of the operation? Distributive property Associative property Commutative property Boolean property
Commutative property
What would be indicated by a vector pointing "southeast" in the GB plane? Conductance and capacitive susceptance Pure susceptance, zero conductance Conductance and inductive susceptance Pure conductance, zero susceptance
Conductance and inductive susceptance
Which of the following is an indirect cost of the accident? Compensation paid to the worker. All of the choices Money paid for the treatment of the worker. Cost of lost time of the injured worker.
Cost of lost time of the injured worker.
Which one of the following laws will not contribute to the Maxwell's equations? Curie Weiss`law Faraday`s law Gauss`law Ampere`s law
Curie Weiss`law
When a diode is doped with either a pentavalent or a trivalent impurity its resistance will: Decrease Increase None of the choices Make the resistance stable against variation due to temperature
Decrease
A choke coil has a resistance to reactance ratio of 0.2. What is the power factor of the choke coil? Less than 0.2 lagging Less than 0.2 leading About 1 About 0
Less than 0.2 lagging
Which one of the following is the address generated by CPU? Logical address Physical address None of the choices Absolute address
Logical address
What circuit implements a combinational logic function by storing a list of output values that correspond to all possible input combinations? Output logic macrocell Parallel logic expander Logic element Look-up table
Look-up table
PLCs that have a fixed amount of I/O capability built into the unit are known as: Rack PLCs None of the choices Monolithic PLCs Modular PLCs
Monolithic PLCs
What device is most likely shown below? Comparator Demultiplexer Parity generator Multiplexer
Multiplexer
A car is raining at a constant speed of 50 km/h, which of the following is the feedback element for the driver? Needle of the speedometer Clutch Steering wheel Eyes
Needle of the speedometer
Loops which do not possess any common node are said to be ___________ loops. Feedback gain Non touching loops Forward gain Touching loops
Non touching loops
To perform product of max terms Boolean function must be brought into: NOT terms NAND terms OR terms AND terms
OR terms
When the microcontroller executes some arithmetic operations, then the flag bits of which of the following register are affected? PC DPTR SP PSW
PSW
Which unit in 80386 DX architecture plays a crucial role in the conversion of linear address to physical address? Segmentation Execution Protection Paging
Paging
Which material is shown in the figure? Diamagnetic material Paramagnetic material Ferromagnetic material Non-magnetic material
Paramagnetic material
Mesh analysis can be used for: Neither planar nor non-planar circuits Planar circuits Non-planar circuits Both planar and non-planar circuits
Planar circuits
When the diode in a half-wave rectifier points toward the load, the output from the rectifier will be: Full-wave Either positive or negative, depending on the polarity of the transformer secondary voltage Negative Positive
Positive
The data-in register of I/O port is ____________. Written by host to start a command Read by controller to get input Written by host to send output Read by host to get input
Read by host to get input
The value of B at H = 0 in a Hysteresis curve is called: Porosity Magnetization Remanence Coercivity
Remanence
Consider the circuit shown below and find whether it satisfies Tellegen's theorem. Satisfies Satisfies only for some elements Satisfies partially Does not satisfy
Satisfies
A uniform magnetic field is directed into the page. A charged particle, moving in the plane of the page, follows a clockwise spiral of decreasing radius as shown. A reasonable explanation is: the charge is positive and speeding up the charge is negative and speeding up the charge is positive and slowing down the charge is negative and slowing down
the charge is negative and slowing down
An electric field is most directly related to: the kinetic energy of a test charge the potential energy of a test charge the force acting on a test charge the momentum of a test charge
the force acting on a test charge
What is the most popular language for PLCs? C++ Ladder diagram OOP+ VHDL
Ladder diagram
The drain characteristics for a FET that you see on a curve tracer are drawn for equal step increases in the V_GS values, yet they are spaced further apart as V_GS values, yet they are spaced further apart as V_GS get closer to zero. Why? Due to the square relation between I_D and V_GS, as V_GS gets closer to zero I_D increases faster so the curves are spaced apart further. This is true for only some FET devices, not all. The curve depends on the FET device used. None of the choices
Due to the square relation between I_D and V_GS, as V_GS gets closer to zero I_D increases faster so the curves are spaced apart further.
In Intel x86 architecture, which general purpose register is used for repeated string instructions as well as shift, rotate and loop instructions? EBP (Data Pointer) EAX (Accumulator) ECX (Counter) EDX (Data register)
ECX (Counter)
Which of the following is true? MOV B, C is a two-byte instruction. Every instruction has two parts i.e. opcode and operands. Maximum number of T-states possible for the execution of an instruction is 16. MVI A, 90H is a three-byte instruction.
Every instruction has two parts i.e. opcode and operands.
What table is not a part of the asynchronous sequential logic analysis procedure? State table Excitation table Flow table Transition table
Excitation table
For an LTI discrete system to be stable, the square sum of the impulse response should be: Zero Integral multiple of 2pi Infinity Finite
Finite
The transition capacitance of a diode is a shunt capacitive effect that occurs when the diode is: Reverse biased Large Forward biased Small
Forward biased
The advantages of negative feedback are: I. higher input impedance II. voltage gain that is more stable III. improved frequency response IV. lower output impedance V. reduced noise in the response
I, II, III, IV and V
If root loci plots of a particular control system do not intersect the imaginary axis at any point, then the gain margin of the system will be: Infinite 1 0 0.707
Infinite
The output of the feedback control system must be a function of: Input and feedback signal Reference input Output and feedback signal Reference output
Input and feedback signal
Which of the following steps have to be followed for interfacing a sensor to a microcontroller 8051? None of the choices Interface sensor with ADC and ADC with 8051 Interface sensor with the MAX232, send now to microcontroller, analyze the results Make the appropriate connections with the controller, ADC conversion, analyze the results
Interface sensor with ADC and ADC with 8051
How is the short circuit reverse transfer admittance (y₁₂) calculated in terms of current and voltage ratio? I₂/ V₁ (keeping V₂ = 0) V₁/ I₂ (keeping I₁ = 0) I₁/ V₂ (keeping V₁ = 0) V₂/ I₁ (keeping I₂ = 0)
I₁/ V₂ (keeping V₁ = 0)
A human body feels comfortable when the heat produced by the metabolism of human body is equal to the: Heat dissipated to the surroundings. Difference of heat dissipated to the surroundings and heat stored in the human body. Heat stored in the human body. Sum of heat dissipated to the surroundings and heat stored in the human body.
Sum of heat dissipated to the surroundings and heat stored in the human body.
What is the difference between a PLA and a PAL? The PAL has more possible product terms than the PLA. The PAL has a programmable OR plane and a programmable AND plane, while the PLA only has a programmable AND plane. The PLA has a programmable OR plane and a programmable AND plane, while the PAL only has a programmable AND plane. PALs and PLAs are the same thing.
The PLA has a programmable OR plane and a programmable AND plane, while the PAL only has a programmable AND plane.
The Light Emitting Diode (LED) emits light of a particular color because: The transition between energy levels of the carriers takes place while crossing the p-n junction. It is fabricated from a fluorescent material. The heat generated in the diode is converted into light. The band gap of the semiconductor material used in the fabrication of the diode is equal to the energy hv of the light photon.
The band gap of the semiconductor material used in the fabrication of the diode is equal to the energy hv of the light photon.
What happens to the parallel output word in an asynchronous binary down counter whenever a clock pulse occurs? The output word increases by 1. The output word increases by 2. The output word decreases by 1. The output word decreases by 2.
The output word decreases by 1.
Which of the following statements is true? The shell life of a resistor is about 1 year. There is no correlation between the physical size of a resistor and its resistance value. Resistors always have axial leads. Resistors are always made from carbon.
There is no correlation between the physical size of a resistor and its resistance value.
Why is a resistor often included in a parallel resonant circuit? To decrease the Q and increase the bandwidth. To increase the Q and decrease bandwidth. To decrease the Q and increase the resonant frequency. To increase the Q and decrease the skin effect.
To decrease the Q and increase the bandwidth.
In assembly language programming, what the purpose of the ORIGIN directive? To indicate the purpose of the code. To list the locations of all the registers used. To indicate the starting position in memory, where the program block is to be stored. To indicate the starting of the computation code.
To indicate the starting position in memory, where the program block is to be stored.
The maximum power drawn from source depends on: Neither source or load resistance Value of load resistance Both source and load resistance Value of source resistance
Value of load resistance
Which elements act as an independent variable in Y-parameters? Voltage Power Current Impedance
Voltage
In a current mirror: neither the i - v curve of compensating diode is similar to collector curve of transistor nor the i - v curve of compensating diode is similar to transconductance curve of transistor the i - v curve of compensating diode is similar to collector curve of transistor either the i - v curve of compensating diode is similar to collector curve of transistor or the i - v curve of compensating diode is similar to transconductance curve of transistor the i - v curve of compensating diode is similar to transconductance curve of transistor
the i - v curve of compensating diode is similar to transconductance curve of transistor
Schokley's equation defines the __________ of the FET and are unaffected by the network in which the device is employed. drain characteristics transfer characteristics V_GS characteristics input output characteristics
transfer characteristics
Which among the following is regarded as short circuit forward transfer admittance? y₂₁ y₁₁ y₁₂ y₂₂
y₂₁
A carbon composition resistor having only three-color stripe has a tolerance of ± 100 % ± 10 % ± 20 % ± 5 %
± 20 %
