Small capacitance HV capacitors can be discharged through high ohmic value resistors of the PTE and PUT type. These resistors, which are designed to handle high voltage for extended durations, can be used to safely discharge the high voltage stored in the capacitors to acceptable voltage levels when the systems are switched off or need reducing for any reason. The PUT and the higher power PTE type resistors can also be used for inrush control in the HV capacitor charging circuits as needed by the circuit designers. In some applications the resistors are immersed in oil tanks to keep them cool and to ensure that there are no corona discharges around them.
