# Floyd Self-test in Power Amplifiers

(Last Updated On: December 8, 2017)

This is the Self-test in Chapter 7: Power Amplifiers from the book Electronic Devices Conventional Current Version, 9th edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

### Floyd Self-test Chapter 7 Topic Outline

• Floyd Self-test in Power Amplifiers
• Floyd Self-test in Class A Power Amplifier
• Floyd Self-test in Class B Power Amplifier
• Floyd Self-test in The Class B and Class AB Push-Pull Amplifiers
• Floyd Self-test in Class C Power Amplifier

### Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. An amplifier that operates in the linear region at all times is

• (a) Class A
• (b) Class AB
• (c) Class B
• (d) Class C

2. A certain class A power amplifier delivers 5 W to a load with an input signal power of 100 mW. The power gain is

• (a) 100
• (b) 50
• (c) 250
• (d) 5

3. The peak current a class A power amplifier can deliver to a load depends on the

• (a) maximum rating of the power supply
• (b) quiescent current
• (c) current in the bias resistors
• (d) size of the heat sink

4. For maximum output, a class A power amplifier must maintain a value of quiescent current that is

• (a) one-half the peak load current
• (b) twice the peak load current
• (c) at least as large as the peak load current
• (d) just above the cutoff value

5. A certain class A power amplifier has The maximum signal power output is

• (a) 6 W
• (b) 12 W
• (c) 1 W
• (d) 0.707 W

6. The efficiency of a power amplifier is the ratio of the power delivered to the load to the

• (a) input signal power
• (b) power dissipated in the last stage
• (c) power from the dc power supply
• (d) none of these answers

7. The maximum efficiency of a class A power amplifier is

• (a) 25%
• (b) 50%
• (c) 79%
• (d) 98%

8. The transistors in a class B amplifier are biased

• (a) into cutoff
• (b) in saturation
• (c) at midpoint of the load line
• (d) right at cutoff

9. Crossover distortion is a problem for

• (a) class A amplifiers
• (b) class AB amplifiers
• (c) class B amplifiers
• (d) all of these amplifiers

10. A BJT class B push-pull amplifier with no transformer coupling uses

• (a) two npn transistors
• (b) two pnp transistors
• (c) complementary symmetry transistors
• (d) none of these

11. A current mirror in a push-pull amplifier should give an ICQ that is

• (a) equal to the current in the bias resistors and diodes
• (b) twice the current in the bias resistors and diodes
• (c) half the current in the bias resistors and diodes
• (d) zero

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

• (a) 25%
• (b) 50%
• (c) 79%
• (d) 98%

13. The output of a certain two-supply class B push-pull amplifier has a VCC of 20 V. If the load resistance is the value of Ic(sat) is

• (a) 5 mA
• (b) 0.4 A
• (c) 4 mA
• (d) 40 mA

14. The maximum efficiency of a class AB amplifier is

• (a) higher than a class B
• (b) the same as a class B
• (c) about the same as a class A
• (d) slightly less than a class B

15. The power dissipation of a class C amplifier is normally

• (a) very low
• (b) very high
• (c) the same as a class B
• (d) the same as a class A

16. The efficiency of a class C amplifier is

• (a) less than class A
• (b) less than class B
• (c) less than class AB
• (d) greater than classes A, B, or AB

17. The transistor in a class C amplifier conducts for

• (a) more than 180 degree of the input cycle
• (b) one-half of the input cycle
• (c) a very small percentage of the input cycle
• (d) all of the input cycle