Abstract: A dimmer for dimming gas discharge and incandescent lamps can be installed in place of a standard wall-mounted light switch and connected to existing wiring. The dimmer has a switch coupling one or more full wave bridge rectifiers to a main AC source and to existing power wires running through the wall to the fixture. The bridge rectifiers are controlled by the dimming switch such that either the normal AC source waveform is transmitted over the power wires, or a full wave positively or negatively rectified AC waveform is transmitted, or else no voltage is transmitted. At the fixture, the transmitted power waveform is applied to the lamp power terminal of the lamp or ballast as well as to a decoder. A dimming interface receives the decoder output and appropriately adjusts lamp brightness by changing the operating conditions of the lamp in accordance with this output. The dimmer may also be used to control general household devices containing a front-end full wave bridge rectifier.