 Amplifiers – Gibilisco MCQs in Electronics

(Last Updated On: December 8, 2017) 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.