Abstract: A load and the main conductions paths of first and second TRIACs are connected in series between first and second power terminals across which an alternating voltage is applied. The first TRIAC is for controlling the power dissipated in the load and the second TRIAC is for unconditionally removing power to the load a predetermined time after the first and second TRIACs are turned-on. The first and second TRIACs are interconnected so that the main terminal 1 (MT1) of one is connected to the main terminal 1 (MT1) of the other at a common point. A control circuit for turning-on and turning-off each TRIAC is connected between the gate electrode of each TRIAC and the common point.

Abstract: A switch, when closed, provides a low impedance conduction path for power being applied to a load and for the operating potential for a control circuit. The control circuit includes timing circuitry which produces a timing signal, a given time after the switch is closed. The timing signal is then used to turn-off the switch causing power to be removed from the load and the control circuit.