# Malvino: MCQ in Power Amplifiers

(Last Updated On: February 7, 2020)

This is the Multiple Choice Questions in Chapter 12: Power Amplifiers from the book Electronic Principles 7th Edition by Albert Malvino. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

### Topic Outline

• MCQs in Amplifier Terms
• MCQs in Two Load Lines
• MCQs in Class A Operation
• MCQs in Class B Operation
• MCQs in Class B Push-Pull Emitter Follower
• MCQs in Biasing Class B and Class AB Amplifiers
• MCQs in Class B and Class AB Drivers
• MCQs in Class C Operation
• MCQs in Class C Formulas
• MCQs in Transistor Power Rating

### Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. An emitter follower has a voltage gain that is

• a. Much less than one
• b. Approximately equal to one
• c. Greater than one
• d. Zero

2. The total ac emitter resistance of an emitter follower equals

• a. re’
• b. re
• c. re + re’
• d. RE

3. The input impedance of the base of an emitter follower is usually

• a. Low
• b. High
• c. Shorted to ground
• d. Open

4. The dc emitter current for class A emitter followers is

• a. The same as the ac emitter current
• b. VE divided by RE
• c. Vc divided by Rc
• d. The same as the load current

5. The ac base voltage of an emitter follower is across the

• a. Emitter diode
• b. DC emitter resistor
• d. Emitter diode and external ac emitter resistance

6. The output voltage of an emitter follower is across the

• a. Emitter diode
• b. DC collector resistor
• d. Emitter diode and external ac emitter resistance

7. If Beta = 200 and re = 150 ohm, the input impedance of the base is approximately

• a. 30 kohm
• b. 600 n
• c. 3 kohm
• d. 5 kohm

8. The input voltage to an emitter follower is usually

• a. Less than the generator voltage
• b. Equal to the generator voltage
• c. Greater than the generator voltage
• d. Equal to the supply voltage

9. The ac emitter current is closest to

• a. VG divided by re
• b. Vin divided by re’
• c. VG divided by re’
• d. Vin divided by re

10. The output voltage of an emitter follower is approximately

• a. 0
• b. VG
• c. Vin
• d. Vcc

11. The ac load line of an emitter follower is usually

• a. The same as the dc load line
• b. More horizontal than the dc load line
• c. Steeper than the dc load line
• d. Vertical

12. If the input voltage to an emitter follower is too large, the output voltage will be

• a. Smaller
• b. Larger
• c. Equal
• d. Clipped

13. If the Q point is at the middle of the dc load line, clipping will first occur on the

• a. Left voltage swing
• b. Upward current swing
• c. Positive half cycle of input
• d. Negative half cycle of input

14. If an emitter follower has VCEQ = 5 V, ICQ = 1 mA, and re = 1 kohm, the maximum peak-to-peak unclipped output is

• a. 1 V
• b. 2 V
• c. 5 V
• d. 10 V

15. If the load resistance of an emitter follower is very large, the external ac emitter resistance equals

• a. Generator resistance
• b. Impedance of the base
• c. DC emitter resistance
• d. DC collector resistance

16. If an emitter follower has re’ = 10 ohm and re = 90 ohm, the voltage gain is approximately

• a. 0
• b. 0.5
• c. 0.9
• d. 1

17. A square wave out of an emitter follower implies

• a. No clipping
• b. Clipping at saturation
• c. Clipping at cutoff
• d. Clipping on both peaks

18. A Darlington transistor has

• a. A very low input impedance
• b. Three transistors
• c. A very high current gain
• d. One VBE drop

19. The ac load line of the emitter follower is

• a. The same as the dc load line
• b. Different from the dc load line
• c. Horizontal
• d. Vertical

20. If the generator voltage is 5 mV in an emitter follower, the output voltage across the load is closest to

• a. 5 mV
• b. 150 mV
• c. 0.25 V
• d. 0.5 V

21. If the load resistor of Fig. 12-la in your textbook is shorted, which of the following are different from their normal values:

• a. Only ac voltages
• b. Only dc voltages
• c. Both dc and ac voltages
• d. Neither dc nor ac voltages

22. If R1 is open in an emitter follower, which of these is true?

• a. DC base voltage is Vcc
• b. DC collector voltage is zero
• c. Output voltage is normal
• d. DC base voltage is zero

23. Usually, the distortion in an emitter follower is

• a. Very low
• b. Very high
• c. Large
• d. Not acceptable

24. The distortion in an emitter follower is

• a. Seldom low
• b. Often high
• c. Always low
• d. High when clipping occurs

25. If a CE stage is direct coupled to an emitter follower, how many coupling capacitors are there between the two stages?

• a. 0
• b. 1
• c. 2
• d. 3

26. A Darlington transistor has a Beta of 8000. If RE = 1 kohm and RL = 100 ohm, the input impedance of the base is closest to

• a. 8 kohm
• b. 80 kohm
• c. 800 kohm
• d. 8 Mohm

27. The transistors of a class B push-pull emitter follower are biased at or near

• a. Cutoff
• b. The center of the dc load line
• c. Saturation
• d. The center of the ac load line

28. Thermal runaway is

• a. Good for transistors
• b. Always desirable
• c. Useful at times
• d. Usually destructive

29. The ac resistance of compensating diodes

• a. Must be included
• b. Is usually small enough to ignore
• c. Compensates for temperature changes
• d. Is very high

30. A small quiescent current is necessary with a class B push-pull amplifier to avoid

• a. Thermal runaway
• b. Destroying the compensating diodes
• c. Crossover distortion
• d. Excessive current drain

31. The zener current in a zener follower is

• a. Equal to the output current
• b. Smaller than the output current
• c. Larger than the output current
• d. Prone to thermal runaway

32. In the two-transistor voltage regulator, the output voltage

• a. Is regulated
• b. Has much smaller ripple than the input voltage
• c. Is larger than the zener voltage
• d. All of the above

33. For a class B push-pull emitter follower to work properly, the emitter diodes must

• a. Be able to control the quiescent current
• b. Have a power rating greater than the output power
• c. Have a voltage gain of I
• d. Match the compensating diodes

34. The maximum efficiency of a class B push-pull amplifier is

• a. 25 percent
• b. 50 percent
• c. 78.5 percent
• d. 100 percent

35. The ac emitter resistance of an emitter follower

• a. Equals the dc emitter resistance
• b. Is larger than the load resistance
• c. Has no effect on MPP
• d. Is usually less than the load resistance

### Complete List of MCQ in Electronic Principles by Albert Malvino

P inoyBIX educates thousands of reviewers and students a day in preparation for their board examinations. Also provides professionals with materials for their lectures and practice exams. Help me go forward with the same spirit.

“Will you subscribe today via YOUTUBE?”

Subscribe