Design principles for junction transistor audio power amplifiers

Junction transistors may be employed as audio frequency power amplifiers which will supply up to several watts of output power. The fact that there are two basic types of transistor (n-p-n and p-n-p) allows a freedom of circuit design which is impossible with electron tubes. In power amplifier design the usual small signal assumptions cannot always be considered valid. Hence, large signal techniques must be applied in order to describe the behavior of the device. The non-linear distortion associated with large signal operation is discussed in terms of the transistor characteristics and methods of reducing this distortion are outlined. Operation in several circuit connections is considered with particular emphasis on the common emitter configuration.