Abstract

A remote switching system in which operation of a load is controlled by signals generated at a remote location and transmitted along an existing AC power line. The system includes a signal transmitter which can be plugged into an AC line socket, and which can operate to place a transient control signal on the AC power line. The system also includes a receiver which is connectable in series with a load to be remotely controlled, and which closes a switching circuit between the AC power line and the load when a switching signal on the power line is detected. The control signals are imposed on the AC line voltage by the transmitter only during an early time in a half-cycle of the power line voltage, before noise transient signals generally appear on the half-cycle, and the receiver is sensitive to control signals only during a corresponding portion of each half-cycle, thereby greatly reducing susceptibility of the switching system to noise on the power line. The receiver is sufficiently compact to fit within a switch box used in conventional household wiring, so that the receiver switch circuit can be connected in parallel with an existing load switch for alternative operation of the load from a remote location. The receiver is constructed to provide a heat transmission path from the internal receiver circuit components which produce heat during operation, to the external load switch and switch box surfaces, from which the heat can be dissipated into the ambient environment.