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1. The output voltage of a power supply is measured at 12 V with no load connected. The
manufacturer’s specifications say the power supply has a regulation of 10 percent. What is the
full-load output voltage of the power supply?
A. 13.2 V
B. 10.9 V
C. 10.8 V
D. 1.2 V
2. A modulation technique that’s used in fiber-optic transmission in which the width of pulses
is varied in accordance with the modulation signal is called
A. PRM.
C. PWM.
B. PPM.
D. PAM.
3. Two electronics technicians are discussing LC and RC oscillators. Technician A says that an
RC oscillator doesn’t require a resonant circuit. Technician B says that an LC oscillator can be
tuned only by varying the inductance, and that an RC oscillator can’t produce a sine wave.
Which of the following statements is correct?
A. Only Technician A is correct.
B. Only Technician B is correct.
C. Both of the technicians are correct.
D. Neither of the two technicians is correct.
4. Look at the four circuit diagrams that are shown in Figure A-1. Which of these four
diagrams represents a correctly configured full-wave bridge rectifier circuit?
A. Circuit 1
C. Circuit 3
B. Circuit 2
D. Circuits 4
5. Which of the following is essential for the operation of an oscillator?
A. Positive feedback
C. A unity gain amplifier
B. Degenerative feedback
D. An LC circuit
6. Look at the circuit diagram and the four waveforms that are shown in Figure A-2. Assume
that diode D1 in the circuit is opened. Which of the four waveforms shown in the figure would
appear across RL?
A. Waveform 1
C. Waveform 3
B. Waveform 2
D. Waveform 4
7. Look at the amplifier circuit shown in Figure A-3. Which of the following statements about
this circuit is correct?
A. This is a common-collector circuit that’s characterized by low input impedance and a high
output impedance.
B. This is a common-collector circuit that’s characterized by a high input impedance and a low
output impedance.
C. This is a common-emitter circuit that’s characterized by a low input impedance and a high
output impedance.
D. This is a common-emitter circuit that’s characterized by a high input
impedance and a low output impedance.
8. Negative clipping of an output signal occurs when the
A. output impedance is too high.
C. input amplitude is too high.
B. input impedance is too high.
D. power supply voltage is too high.
9. Look at the circuit diagram shown in Figure A-4. When R1 and R2 are equally illuminated,
the lamp I1 glows dimly. Which of the following will happen if R2 is covered so that no light
can reach it?
A. Lamp I1 glows brighter, because the forward bias on Q1 is decreased.
B. Lamp I1 goes out, because the forward bias on Q1 is decreased.
C. Lamp I1 glows brighter, because the voltage on the base of Q1 goes positive.
D. Lamp I1 goes out, because the forward bias on Q1 increases.
10. One advantage of using photon coupling for signal transmission is the
A. lower power required for transmission.
B. greater immunity to noise pickup
C. lower cost of signal-handling components
D. greater adaptability to digital transmission
11. A full-wave power supply with a capacitor-input filter is connected to a 400 Hz AC source.
The frequency of the ripple waveform at the input to the filter is
A. 0 Hz (DC).
C. 400 Hz.
B. 100 Hz.
D. 800 Hz.
12. Look at the circuit diagram shown in the figure A-5.what is the power level at point B in
the circuit?
(A) 0.31mW (B) 3.1mW (c) 62mW (d) 620mW
13. In the circuit diagram shown in the figure A-5.what is the power level at point A
(A) 0.31mW (B) 3.1mW (c)31mW
(D) 310mW
14. What would happen at the output of a full-wave bridge rectifier circuit if one of the diodes
in the bridge opened?
A. The ripple frequency would decrease, and the voltage would decrease.
B. The ripple frequency would increase, and the voltage would decrease.
C. The ripple frequency would remain the same, and the voltage would decrease.
D. The ripple frequency would remain the same, and the voltage would increase.
15. Look at the four circuit diagrams shown in Figure A-6. Which of these four diagrams shows
a correctly biased Class A amplifier?
A. Circuit 1
C. Circuit 3
B. Circuit 2
D. Circuit 4
16. Two electronics technicians are comparing a full-wave bridge rectifier to a full-wave
rectifier that uses two diodes and a center-tapped secondary. Technician A says that the twodiode rectifier has a lower ripple frequency and can supply greater current than the full-wave
bridge rectifier. Technician B says that the full wave bridge rectifier results in full secondary
voltage at the output. Which of the following statements is correct?
A. Only Technician A is correct.
B. Only Technician B is correct.
C. Both of the technicians are correct.
D. Neither of the two technicians is correct.
17. Look at the circuit diagram and four waveforms that are shown in the figure.
Assume that the circuit’s switch is closed momentarily, then opened. Which of the four
waveforms shown will appear between terminals A and B after the switch is opened?
A). waveform 1
B) waveform 2
(c) waveform 3
(D) waveform 4
18. A 100 kHz oscillator that’s followed by a doubler and two triplers will produce an output
frequency of
(A) 180kHz (B) 500 kHz (c) 800kHz
(D) 1.8 MHz
19. Look at the circuit diagram shown in the fig A-8. What is the voltage between point A and
ground?
(A)+6V
(B) -6V
(c) +25V
(D)-25V
Answer: Assuming those are Zener diodes. Without the diodes, the potential across the first
two resistors would be 12V each. This is greater than the potential of the diode, so the current
flows through the diode and the potential across each of the first two resistors is 5V. This
means the potential across the third resistor is 20 V.
So the potential from point A to the ground is +25V
20. In the circuit shown in fig A-8 what is the current through R2?
(A) 25mA
(B) 60mA
(C) 2.5mA
(D) 6.00mA
Answer: V = 5 volts, R = 2 k
so
I = V/R = 5 / 2 =
2.5 milliamps