Element 3
What does the power factor equal in an R-L circuit having a 60 degree phase angle between the voltage and the current? [3-13B1]
0.5
What does the power factor equal in an R-L circuit having a 30 degree phase angle between the voltage and the current? [3-13B6]
0.866
By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value? [3-6A5]
0.9
How many bits of information can be stored in a single flip-flop circuit? [3-36E4]
1
What is the RMS value of a 340-volt peak-to-peak pure sine wave? [3-12B5]
120 volts AC.
In polar coordinates, what is the impedance of a network composed of a 100-ohm-reactance inductor in series with a 100-ohm resistor? [3-17B2]
141 ohms, /45 degrees
In rectangular coordinates, what is the impedance of a network composed of a 1.0-millihenry inductor in series with a 200-ohm resistor, at 30 kHz? [3-16B4]
200 + j188
What is the most the actual transmit frequency could differ from a reading of 462,100,000 Hertz on a frequency counter with a time base accuracy of +/-0.1 ppm? [3-11B1]
46.21 Hz.
What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in series? [3-15B2]
47 seconds.
After two time constants, the capacitor in an RC circuit is charged to what percentage of the supply voltage? [3-14B5]
86.5 %
In Figure 3B2, what is the voltage drop across R1? [3-10B5]
9 volts.
What frequency synthesizer circuit uses a phase comparator, look-up table, digital-to-analog converter, and a low-pass antialias filter? [3-31D1]
A direct digital synthesizer.
What turns ratio does a transformer need in order to match a source impedance of 500 ohms to a load of 10 ohms? [3-18B4]
7.1 to 1
What is the approximate magnitude of the impedance of a series R-L-C circuit at resonance? [3-29D2]
Approximately equal to the circuit resistance.
What are the elements of a unijunction transistor? [3-25C4]
Base 1, base 2, and emitter.
What are the three terminals of a bipolar transistor? [3-25C2]
Base, collector and emitter.
The frequency of an AC signal can be divided electronically by what type of digital circuit? [3-37E1]
Bistable multivibrator.
In a positive-logic circuit, what level is used to represent a logic 1? [3-35E4]
High level
What is the meaning of the term "alpha" with regard to bipolar transistors? The change of: [3-25C1]
Collector current with respect to emitter current.
What do the initials CMOS stand for? [3-28C3]
Complementary metal-oxide semiconductor.
In the op-amp oscillator circuit shown in Figure 3D6, what would be the most noticeable effect if the capacitance of C were suddenly doubled? [3-30D6]
Frequency would be lower.
Where is the external feedback network connected to control the gain of a closed-loop op-amp circuit? [3-30D4]
From output to the inverting input.
What are the three terminals of a TRIAC? [3-23C5]
Gate, anode 1, and anode 2.
Which of the 4 groups of metals listed below are the best low-resistance conductors? [3-4A3]
Gold, Silver, and COPPER.
In a linear electronic voltage regulator: [3-22C1]
The conduction of a control element is varied in direct proportion to the line voltage or load current.
What determines the visible color radiated by an LED junction? [3-27C2]
The materials used to construct the device.
What does the photoconductive effect in crystalline solids produce a noticeable change in? [3-19C3]
The resistance of the solid.
What special type of diode is capable of both amplification and oscillation? [3-24C4]
Tunnel diodes.
When an NPN transistor is operating as a Class A amplifier, the base-emitter junction: [3-26C6]
Is forward biased and the collector-base junction is reverse biased.
What happens to the conductivity of photoconductive material when light shines on it? [3-19C1]
It increases.
What describes a diode junction that is forward biased? [3-28C1]
It is a low impedance.
What are the two most commonly-used specifications for a junction diode? [3-5A1]
Maximum forward current and PIV (peak inverse voltage).
What is the characteristic of the current flow within the parallel elements in a parallel R-L-C circuit at resonance? [3-29D5]
Maximum.
A transformer used to step up its input voltage must have: [3-21C2]
More turns of wire on its secondary than on its primary.
A common emitter amplifier has: [3-5A5]
More voltage gain than a common collector.
What will occur if an amplifier input signal coupling capacitor fails open? [3-32D3]
No amplification will occur, with DC within the circuit measuring normal.
What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the supply voltage? [3-14B1]
One time constant.
What is the main advantage of using an op-amp audio filter over a passive LC audio filter? [3-30D1]
Op-amps exhibit gain rather than insertion loss.
An R-S flip-flop is capable of doing all of the following except: [3-36E6]
Operate in toggle mode with R-S inputs held constant and CLK initiated.
An LED facing a photodiode in a light-tight enclosure is commonly known as a/an: [3-27C5]
Optoisolator.
What is a characteristic of a NOR gate? [3-34E4]
Produces a logic "0" at its output if any or all inputs are logic "1".
What is a characteristic of a NAND gate? [3-34E2]
Produces a logic "0" at its output only when all inputs are logic "1".
What is a characteristic of an OR gate? [3-34E3]
Produces a logic "1" at its output if any input is logic "1".
What is one common use for PIN diodes? [3-24C1]
RF switch.
What is the term for the out-of-phase power associated with inductors and capacitors? [3-1A6]
Reactive power.
How might you reduce the inductance of an antenna coil? [3-4A6]
Reduce the number of turns
The opposition to the creation of magnetic lines of force in a magnetic circuit is known as: [3-2A4]
Reluctance.
Which metal object may be least affected by galvanic corrosion when submerged in seawater? [3-3A3]
Stainless steel propeller shaft.
What is the transistor called that is fabricated as two complementary SCRs in parallel with a common gate terminal? [3-23C4]
TRIAC.
What is a common use of a hot-carrier diode? [3-24C2]
VHF and UHF mixers and detectors.
At pi/3 radians, what is the amplitude of a sine-wave having a peak value of 5 volts? [3-12B1]
+4.3 volts.
What is the relative dielectric constant for air? [3-3A2]
1.
What is the most the actual transmitter frequency could differ from a reading of 156,520,000 Hertz on a frequency counter with a time base accuracy of +/- 1.0 ppm? [3-11B4]
156.52 Hz.
What is the most the actual transmitter frequency could differ from a reading of 156,520,000 Hertz on a frequency counter with a time base accuracy of +/- 10 ppm? [3-11B5]
1565.20 Hz.
In rectangular coordinates, what is the impedance of a network composed of a 0.01-microfarad capacitor in parallel with a 300-ohm resistor, at 50 kHz? [3-16B5]
159 - j150
What is the magnitude of the impedance of a series AC circuit having a resistance of 6 ohms, an inductive reactance of 17 ohms, and zero capacitive reactance? [3-18B1]
18 ohms.
With a pure AC signal input to the circuit shown in Figure 3D11, what output wave form would you expect to see on an oscilloscope display? [3-32D6]
2
Which lamps would be lit in the circuit shown in Figure 3D8? [3-32D2]
2, 3, 4, 7 and 8.
A 1-watt, 10-volt Zener diode with the following characteristics: Imin. = 5 mA; Imax. = 95 mA; and Z = 8 ohms, is to be used as part of a voltage regulator in a 20-V power supply. Approximately what size current-limiting resistor would be used to set its bias to the midpoint of its operating range? [3-18B2]
200 ohms.
What is the time constant of a circuit having a 220-microfarad capacitor and a 1-megohm resistor in parallel? [3-15B4]
220 seconds.
What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors all in parallel? [3-15B1]
220 seconds.
In polar coordinates, what is the impedance of a network comprised of a 400-ohm-reactance inductor in parallel with a 300-ohm resistor? [3-17B5]
240 ohms, /36.9 degrees
A transformer primary of 2250 turns connected to 120 VAC will develop what voltage across a 500-turn secondary? [3-21C3]
26.7 volts.
If a current of 3 amperes flows through a resistor connected to 90 volts, what is the resistance? [3-9B5]
30 ohms.
A 500-ohm, 2-watt resistor and a 1500-ohm, 1-watt resistor are connected in parallel. What is the maximum voltage that can be applied across the parallel circuit without exceeding wattage ratings? [3-10B3]
31.6 volts.
A relay coil has 500 ohms resistance, and operates on 125 mA. What value of resistance should be connected in series with it to operate from 110 V DC? [3-9B6]
380 ohms.
What value of series resistor would be needed to obtain a full scale deflection on a 50 microamp DC meter with an applied voltage of 200 volts DC? [3-9B1]
4 megohms.
In rectangular coordinates, what is the impedance of a network composed of a 10-microhenry inductor in series with a 40-ohm resistor, at 500 MHz? [3-16B3]
40 + j31400
In Figure 3B1, what is the voltage drop across R1? [3-10B4]
5 volts.
What is the common power supply voltage for TTL series integrated circuits? [3-33E3]
5 volts.
A power transformer has a primary winding of 200 turns of #24 wire and a secondary winding consisting of 500 turns of the same size wire. When 20 volts are applied to the primary winding, the expected secondary voltage will be: [3-21C6]
50 volts.
RF input to a mixer is 200 MHz and the local oscillator frequency is 150 MHz. What output would you expect to see at the IF output prior to any filtering? [3-31D3]
50, 150, 200 and 350 MHz.
In polar coordinates, what is the impedance of a network composed of a 300-ohm-reactance capacitor, a 600-ohm-reactance inductor, and a 400-ohm resistor, all connected in series? [3-17B4]
500 ohms, /37 degrees
What is a monostable multivibrator? [3-37E3]
A circuit that can be switched momentarily to the opposite binary state and then returns after a set time to its original state.
For the logic input levels given in Figure 3E13, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.) [3-35E3]
A is high, B is high and C is high.
For the logic input levels shown in Figure 3E12, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.) [3-35E2]
A is low, B is high and C is high.
What is the definition of a phase-locked loop (PLL) circuit? [3-31D6]
A servo loop consisting of a phase detector, a low-pass filter and voltage-controlled oscillator.
What is meant by the term "back EMF"? [3-2A5]
A voltage that opposes the applied EMF.
What is the description of a square wave? [3-7A4]
A wave that abruptly changes back and forth between two voltage levels and stays at these levels for equal amounts of time.
What is a sine wave? [3-7A1]
A wave whose amplitude at any given instant can be represented by the projection of a point on a wheel rotating at a uniform speed.
In Figure 3C5, the 1 uF capacitor is connected to a potentiometer that is used to: [3-20C5]
Adjust tone.
What are the three terminals of an SCR? [3-23C2]
Anode, cathode, and gate.
Determine the phase relationship between the two signals shown in Figure 3B3. [3-12B6]
B is lagging A by 90 degrees.
What factors determine the capacitance of a capacitor? [3-20C1]
Distance between the plates and the dielectric constant of the material between the plates.
Halving the cross-sectional area of a conductor will: [3-8A3]
Double the resistance.
If a resistance to which a constant voltage is applied is halved, what power dissipation will result? [3-13B2]
Double.
What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope? [3-6A4]
Peak-to-peak.
How could voltage be greater across reactances in series than the applied voltage? [3-29D3]
Resonance.
What is the term used to identify an AC voltage that would cause the same heating in a resistor as a corresponding value of DC voltage? [3-8A1]
Root mean square (RMS).
What type of wave is characterized by a rise time significantly faster than the fall time (or vice versa)? [3-7A6]
Sawtooth wave.
What determines the strength of the magnetic field around a conductor? [3-2A1]
The amount of current.
What happens to the conductivity of a photosensitive semiconductor junction when it is illuminated? [3-19C5]
The junction resistance decreases.
What limits the maximum forward current in a junction diode? [3-5A2]
The junction temperature.
What does it mean for a transistor to be cut off? [3-26C2]
There is no current between emitter and collector.
Why are special precautions necessary in handling FET and CMOS devices? [3-28C2]
They are susceptible to damage from static charges.
What is the basic unit of electrical power? [3-1A2]
Watt.
What formula would determine the inductive reactance of a coil if frequency and coil inductance are known? [3-1A5]
XL = 2 pi f L
What device is usually used as a stable reference voltage in a linear voltage regulator? [3-22C3]
Zener diode.
What is the voltage range considered to be valid logic low input in a TTL device operating at 5 volts? [3-33E1]
Zero to 0.8 volts.
