Analysis of linear time-varying circuits by the Brillouin-Wentzel-Kramers method

This paper presents a general mathematical technique for studying the response of linear time-varying circuits that contain parameters whose magnitudes vary in a periodic manner with the time. The method presented is based on the Brillouin-Wentzel-Kramers (BWK) procedure, which has been widely used in connection with problems of wave mechanics. This method gives approximate results with very little error if the variable circuit elements exhibit small variations about a large average value. The application of the method to circuit problems is illustrated by using it to study the free and forced oscillations of typical series circuits that contain periodic capacitance, resistance, and inductance parameters.