Abstract: An inverter power supply system (DC input, AC output) with a bridge type power stage having switching devices (transistors) in each arm is used to create an AC output voltage across the bridge center terminals. The transistors execute numerous switching cycles per period to create an output waveform that has a low frequency AC component together with a high frequency AC component that is removed via a low pass filter. Unless some means is provided to prevent it, a DC component is usually present at the output of the inverter as well. This DC component will cause saturation in transformer coupled loads with attendant excessive inverter device currents unless means are provided to limit or eliminate the DC component of the output voltage.