Chapter Overview

This chapter introduces the idea of efficiency in an amplifier. An efficient amplifier delivers a large part of the power it receives from the supply as a useful output signal. Efficiency is most important when large amounts of signal power are required. It will be shown that amplifier efficiency is related to how the amplifier is biased. It is possible to make large improvements in efficiency by moving the operating point away from the center of the load line.

This chapter will help you to:

1. Calculate amplifier efficiency.

2. Identify the class of amplifier operation.

3. Recognize crossover distortion in push-pull amplifiers.

4. Explain the operation of complementary symmetry amplifiers.

5. Describe tank circuit action in class C amplifiers.

6. Explain how class D amplifiers work.

Study Outline

8-1 Amplifier Class

8-2 Class A Power Amplifiers

8-3 Class B Power Amplifiers

8-4 Class AB Power Amplifiers

8-5 Class C Power Amplifiers

8-6 Switch-Mode Amplifiers