Analysis of the effects of shunt capacitance on the performance of pulse modulators

An accurate analysis of the effects of shunt capacitance and/or the resultant transient waveform on the power dissipation of short-pulse modulators or similar switching devices is conducted. Expressions representing the transient waveform and average current are derived. A graphical approach provides the transient waveform together with the parameter values for evaluating the expressions. A numerical example showing the performance of an actual short-pulse test modulator is in good agreement with the experimental value. The example indicates that the presence of a 70-pF shunt capacitance produces an average plate current of more than twice the value, and a plate dissipation of more than 15 times the value, that could be obtained in the absence of the shunt capacitance