Abstract: An electronic high frequency supply, such as a lamp ballast, having a full-wave rectifier, a storage capacitor charged to a voltage greater than the peak of the rectifier output, and an isolating diode between the rectifier and the diode. An inverter is connected to the energy storage capacitor, and has a high frequency inductive load circuit connected between the inverter output and a junction between the isolating diode and the storage capacitor. A capacitor, connected to the junction in parallel with a series circuit formed by the isolating diode and storage capacitor, forms a high frequency resonance circuit with the inductive load circuit. Current is drawn from the rectifier only as a series of pulses at the inverter frequency. To minimize variation in the high frequency load current, the inverter frequency is varied according to a sensed parameter which varies during each cycle of the rectifier output.