Abstract: A power supply circuit for conducting current from an ac voltage source to an associated electrical load having a power supply circuit for feeding current to the load in alternate half cycles. The circuit comprises in combination with an ac voltage source and first circuit for conducting current in one direction through the load in a first half cycle and second circuit for conducting current through the load in the opposing direction in a second half cycle, the first and second circuit being responsive to the positive and negative cycling of the ac voltage source; a first switching control responsive to the positive half of the sinusoidal voltage waveform from the ac voltage source for energizing the first circuit and a second switching control responsive to the negative half of the sinusoidal voltage waveform from the ac voltage source for energizing the second circuit.