Design principles of junction transistor audio amplifiers

The junction transistor may be represented as an active network in terms of various two-terminal pair equivalent circuits. The principles of design of audio-frequency amplifiers consisting of one or more transistor stages may be outlined in terms of these equivalent circuits. The effects of applying feedback to the amplifier configurations are discussed. Various methods for minimizing drifts of the quiescent point of operation of transistor amplifier stages are considered. Signal-to-noise ratios, important in the design of high quality amplifiers, are developed in terms of device noise figures.