Definition of small-signal amplifier
Some amplifiers are required to deliver an output voltage or output current which is small compared with the maximum that the amplifier could deliver. When a voltage output is wanted, the magnitude of the current output is usually of little consequence provided the transistor(s) can supply it without distortion. Similarly if the amplifier is designed to supply a current output, the magnitude of the voltage output is of secondary importance provided it is not sufficient to cause overloading and distortion. Such amplifiers are termed small-signal amplifiers: typical examples are microphone head amplifiers and the r.f. and early i.f. stages in a receiver.