The application of power series to the solution of non-linear circuit problems

It is shown that Carson´s power series solution of a triode circuit may be extended to the case in which the triode is associated with a linear network of any form. The reduction of non-linear distortion in an amplifier by negative feedback is discussed. The conditions of stability for a triode circuit are derived, and it is shown that the solution remains convergent even when the circuit is regenerative, failing completely only at the point of critical regeneration. When the circuit is unstable and an e.m.f. near the natural frequency is applied, the solution represents an unstable oscillation, but, when the applied frequency is not near resonance, the solution will represent a stable forced oscillation if the amplitude is sufficiently large.