An engineering approach to the design of transistor feedback amplifiers

A technique is developed for the design of transistor feedback amplifiers, based on the use of impedance mismatches between stages. Expressions are derived for the transmittance of the four basic building blocks¿the series and shunt single stage feedback amplifiers and the current and voltage feedback pairs¿and methods of interconnection which achieve the mismatch are considered. The expressions for the transmittance are both simple and highly accurate, yet they involve no quantitative information about the transistors at all. It is concluded that transistor circuitry is far more designable than valve circuitry. Three examples in the use of the design philosophy are given, covering the audio and video frequency ranges up to 20 Mc/s.