This is part of a precision High Voltage but Low current Power Supply for Testing leakage currents in passive devices. This Supply is a module for a Automatic Test system in component inspection.
HV Precision Power Supply Circuits
Insulation of Transformers and the Isolation of plastic capacitors are best analyzed by applying a High Voltage and measuring the leakage currents.
These currents are in the order of nano-amps and pico-amps; values close to the bias-currents and leakage currents of devices. Some offsets and corrections can be done in software for the ATE systems.