This is the Multiple Choice Questions (MCQs) in Chapter 24: Amplifiers from the book Teach Yourself Electricity and Electronics, 5th edition by Stan Gibilisco. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.
Start Practice Exam Test Questions
1. The decibel is a unit of:
- A. Relative signal strength.
- B. Voltage.
- C. Power.
- D. Current.
2. If a circuit has a voltage-amplification factor of 20, then the voltage gain is:
- A. 13 dB.
- B. 20 dB.
- C. 26 dB.
- D. 40 dB.
3. A gain of -15 dB in a circuit means that:
- A. The output signal is stronger than the input.
- B. The input signal is stronger than the output.
- C. The input signal is 15 times as strong as the output.
- D. The output signal is 15 times as strong as the input.
4. A device has a voltage gain of 23 dB. The input voltage is 3.3 V. The output voltage is:
- A. 76 V.
- B. 47 V.
- C. 660 V.
- D. Not determinable from the data given.
5. A power gain of 44 dB is equivalent to an output/input power ratio of:
- A. 44.
- B. 160.
- C. 440.
- D. 25,000.
6. A resistor between the base of an NPN bipolar transistor and the positive supply voltage is used to:
- A. Provide proper bias.
- B. Provide a path for the input signal.
- C. Provide a path for the output signal.
- D. Limit the collector current.
7. The capacitance values in an amplifier circuit depend on:
- A. The supply voltage.
- B. The polarity.
- C. The signal strength.
- D. The signal frequency.
8. A class-A circuit would not work well as:
- A. A stereo hi-fi amplifier.
- B. A television transmitter PA.
- C. A low-level microphone preamplifier.
- D. The first stage in a radio receiver.
9. In which of the following FET amplifier types does drain current flow for 50 percent of the signal cycle?
- A. Class A.
- B. Class AB1.
- C. Class AB2.
- D. Class B.
10. Which of the following amplifier types produces the least distortion of the signal waveform?
- A. Class A.
- B. Class AB1.
- C. Class AB2.
- D. Class B.
11. Which bipolar amplifier type has some distortion in the signal wave, with collector current during most, but not all, of the cycle?
- A. Class A.
- B. Class AB1.
- C. Class AB2.
- D. Class B.
12. How can a class-B amplifier be made suitable for hi-fi audio applications?
- A. By increasing the bias.
- B. By using two transistors in push-pull.
- C. By using tuned circuits in the output.
- D. A class-B amplifier cannot work well for hi-fi audio.
13. How can a class-C amplifier be made linear?
- A. By reducing the bias.
- B. By increasing the drive.
- C. By using two transistors in push-pull.
- D. A class-C amplifier cannot be made linear.
14. Which of the following amplifier classes generally needs the most driving power?
- A. Class A.
- B. Class AB1.
- C. Class AB2.
- D. Class B.
15. A graphic equalizer is a form of:
- A. Bias control.
- B. Gain control.
- C. Tone control.
- D. Frequency control.
16. A disadvantage of transfer coupling, as opposed to capacitive coupling, is that:
- A. Transformers can’t match impedances.
- B. Transformers can’t work above audio frequencies.
- C. Transformers cost more.
- D. Transformers reduce the gain.
17. A certain bipolar-transistor PA is 66 percent efficient. The output power is 33 W. The dc collector power input is:
- A. 22 W.
- B. 50 W.
- C. 2.2 W.
- D. None of the above.
18. A broadband PA is:
- A. Generally easy to use.
- B. More efficient than a tuned PA.
- C. Less likely than a tuned PA to amplify unwanted signals.
- D. Usable only at audio frequencies.
19. A tuned PA must always be:
- A. Set to work over a wide range of frequencies.
- B. Adjusted for maximum power output.
- C. Made as efficient as possible.
- D. Operated in class C.
20. A loading control in a tuned PA:
- A. Provides an impedance match between the bipolar transistor or FET and the load.
- B. Allows broadband operation.
- C. Adjusts the resonant frequency.
- D. Controls the input impedance.
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