A Nonlinear Theory of Class C Transistor Amplifiers and Frequency Multipliers

A new theory of class C amplifiers and frequency multipliers is developed on the basis of the large-signal Ebers-Moll equations. It is shown that both collector efficiency and power gain can be calculated as closed functions of input level for all orders of multiplication. The results are obtained without recourse to graphical methods or to piecewise-linear approximations; neither is it necessary to invoke the concept of conduction angle. Expressions are derived for the maximum efficiency and gain attainable with a given transistor under ideal conditions. The theoretical results are presented as normalized curves and are in excellent agreement with measurement at low frequencies. An approximate treatment of the high-frequency case is also given.