Abstract: A high voltage switching circuit is provided for electrically coupling, or decoupling, a high voltage power supply to, or from, a load selectively in accordance with a control signal. The circuit converts the control signal to a radiant energy signal. A plurality of switching modules serially is coupled between the load and the high voltage power supply, each one of such modules including drive circuitry for converting the radiant energy into drive signals for a switching transistor which drives such transistor between a conducting and non-conducting condition selectively in accordance with the drive signal. With such arrangement, each of the modules develops its own drive signal in response to the radiant energy signal so that each drive signal is self-referenced to the reference potential of the module.