1. For class B operation, the collector current flows
a. The whole cycle
b. Half the cycle
c. Less than half a cycle
d. Less than a quarter of a cycle
b
2. Transformer coupling is an example of
a. Direct coupling
b. AC coupling
c. DC coupling
d. Impedance coupling
b
3. An audio amplifier operates in the frequency range of
a. 0 to 20 Hz
b. 20 Hz to 20 kHz
c. 20 to 200 kHz
d. Above 20 kHz
b
4. A tuned RF amplifier is
a. Narrowband
b. Wideband
c. Direct coupled
d. Impedance coupled
a
5. The first stage of a preamp is
a. A tuned RF stage
b. Large signal
c. Small signal
d. A dc amplifier
c
6. For maximum peak-to-peak output voltage, the Q point should be
a. Near saturation
b. Near cutoff
c. At the center of the dc load line
d. At the center of the ac load line
d
7. An amplifier has two load lines because
a. It has ac and dc collector resistances
b. It has two equivalent circuits
c. DC acts one way and ac acts another
d. All of the above
d
8. When the Q point is at the center of the ac load line, the maximum peak-to-peak output voltage equals
a. VCEQ
b. 2VCEQ
c. ICQ
d. 2IcQ
b
9. Push-pull is almost always used with
a. Class A
b. Class B
c. Class C
d. All of the above
b
10. One advantage of a class B push-pull amplifier is
a. Very small quiescent current drain
b. Maximum efficiency of 78.5 percent
c. Greater efficiency than class A
d. All of the above
d
11. Class C amplifiers are almost always
a. Transformer-coupled between stages
b. Operated at audio frequencies
c. Tuned RF amplifiers
d. Wideband
c
12. The input signal of a class C amplifier
a. Is negatively clamped at the base
b. Is amplified and inverted
c. Produces brief pulses of collector current
d. All of the above
d
13. The collector current of a class C amplifier
a. Is an amplified version of the input voltage
b. Has harmonics
c. Is negatively clamped
d. Flows for half a cycle
b
14. The bandwidth of a class C amplifier decreases when the
a. Resonant frequency increases
b. Q increases
c. XL decreases
d. Load resistance decreases
b
15. The transistor dissipation in a class C amplifier decreases when the
a. Resonant frequency increases
b. coil Q increases
c. Load resistance decreases
d. Capacitance increases
b
16. The power rating of a transistor can be increased by
a. Raising the temperature
b. Using a heat sink
c. Using a derating curve
d. Operating with no input signal
b
17. The ac load line is the same as the dc load line when the ac collector resistance equals the
a. DC emitter resistance
b. AC emitter resistance
c. DC collector resistance
d. Supply voltage divided by collector current
c
18. If RC = 3.6 kohm and RL = 10 kohm, the ac load resistance equals
a. 10 kohm
b. 2.65 kohm
c. I kohm
d. 3.6 kohm
b
19. The quiescent collector current is the same as the
a. DC collector current
b. AC collector current
c. Total collector current
d. Voltage-divider current
a
20. The ac load line usually
a. Equals the dc load line
b. Has less slope than the dc load line
c. Is steeper than the dc load line
d. Is horizontal
c
21. For a Q point near the center of the dc load line, clipping is more likely to occur on the
a. Positive peak of input voltage
b. Negative peak of output voltage
c. Positive peak of output voltage
d. Negative peak of emitter voltage
c
22. In a class A amplifier, the collector current flows for
a. Less than half the cycle
b. Half the cycle
c. Less than the whole cycle
d. The entire cycle
d
23. With class A, the output signal should be
a. Unclipped
b. Clipped on positive voltage peak
c. Clipped on negative voltage peak
d. Clipped on negative current peak
a
24. The instantaneous operating point swings-along the
a. AC load line
b. DC load line
c. Both load lines
d. Neither load line
a
25. The current drain of an amplifier is the
a. Total ac current from the generator
b. Total dc current from the supply
c. Current gain from base to collector
d. Current gain from collector to base
b
26. The power gain of an amplifier
a. Is the same as the voltage gain
b. Is smaller than the voltage gain
c. Equals output power divided by input power
d. Equals load power
c
27. Heat sinks reduce the
a. Transistor power
b. Ambient temperature
c. Junction temperature
d. Collector current
c
28. When the ambient temperature increases, the maximum transistor power rating
a. Decreases
b. Increases
c. Remains the same
d. None of the above
a
29. If the load power is 3 mW and the dc power is 150 mW, the efficiency is
a. 0
b. 2 percent
c. 3 percent
d. 20 percent
b
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