Calculation and Design of Class C Amplifiers

A method of calculating the performance of class C triode amplifiers is presented which is based on the assumption that the total space current (Ip+Ig) is proportional to (Eg+Ep/μ)^α, where α is a constant, usually close to three halves. The direct-current and fundamental alternating-current components of such a space current pulse are presented (graphically) as a function of the angle of current flow, for various values of α, and it is shown how to obtain the plate current components by estimating the direct grid current, and correcting for the current diverted to the grid. It is shown how the results of the analysis may be applied in a straightforward manner to lay out class C amplifiers on paper, and to predict power output, power input, plate loss, etc., for any particular set of operating conditions. The method is applied to several examples and the accuracy shown to be satisfactory for all ordinary design requirements.