Small Signal Amplification

Abstract

The devices and circuits described so far have not allowed direct connection of input signals from, say, a microphone or an oscillator, nor have they allowed direct connection to, say, another amplifier or measuring instrument. So that a complete electronic circuit may be constructed using a transistor or triode, additional components must be added for biasing, decoupling, coupling and so on; this chapter describes the simple amplifier circuits using just one transistor or one triode and concentrates only on small signal amplification as opposed to power amplification such as that used to drive a loudspeaker where more complex designs are required (these are described at Level III). The transistor amplifier is first described using some simple design techniques and these are then analysed to find the gains; a similar section on the triode amplifier follows. Chapters 5 and 6 illustrate two more types of application for the transistor and triode with oscillators and logic circuits.