Abstract: An apparatus for applying a variable voltage to an electric load utilizes a transformer with several taps to provide different voltage levels for the load. The load is connected to alternate taps by a switching device, which is operated by a control device responsive to short interruptions in the power supply to the load. Short interruptions in power can be generated by rapidly turning one or more existing power switches in circuit with the load off and on again, so remote control is possible from several locations. Apparatus with the above structure is particularly suitable while employing a toroidal transformer for dimmer control of halogen lamps.