A device which, through its self-oscillation, generates a stable high voltage DC or AC output from a low voltage DC input. The device automatically maintains a desired voltage on an output capacitor, despite changes in output load or input voltage. The device is capable of dead-short operation, capacitor charging, high voltage step-up, high efficiency, and high power density. The capability to step up low voltage to high voltage in such a manner paves the way for advancement in battery-to-grid inverter technology, portable welding devices, portable medical devices, aircraft and spacecraft propulsion devices among many other areas.