Abstract: The present invention is directed to a power supply circuit for controlling a load which, for example, includes both a gas-discharge lamp and an auxiliary load. The power supply circuit includes a ballast circuit for limiting current supplied to the gas discharge lamp. The auxiliary load, such as an occupancy sensor, is connected to receive an alternating current signal from a transformer winding, inductor coil, or other suitable portion of the ballast circuit. The power supply circuit includes a rectifier for rectifying the alternating current signal to provide a stable, low-voltage direct current signal to drive the auxiliary load.

Abstract: The present invention is directed to providing building automation systems which can effectively control light output of a building in a manner which can significantly reduce power consumption, yet which goes virtually unnoticed by building occupants. Exemplary embodiments are directed to using existing building automation systems to control the dimming, rather than the turning off, of selected artificial lighting. Further, exemplary embodiments are directed to using the conventional relay network of existing building automation systems to control the dimming of the artificial lighting.