Inventors:
Louis M. Sandler - North Reading MA
Walter R. Spofford - Bedford MA
Charles E. Scott - Noblesville IN
Assignee:
Emhart Industries, Inc. - Indianapolis IN
International Classification:
G05F 304
Abstract:
A circuit for controlling the application of alternating current power to an apparatus provides a triac having a pair of main terminals adapted for being coupled in series between the apparatus and a source of alternating current power, the triac also having a gate terminal, nonregulated direct current power supply adapted to receive alternating current power from the source thereof, the power supply including a rectifier and a filter and having a pair of output terminals for distributing direct current power, circuitry for maintaining an approximately constant load on the nonregulated direct current power supply and for switching current therefrom to the triac gate terminal including a semiconductor junction switch having a gate terminal, a first main terminal coupled to one output terminal of the power supply and the triac gate terminal and a second main terminal coupled to the other output terminal of the power supply, and circuitry coupled to the switch gate terminal for activating and deactivating current flow in the switch to deactivate and activate, respectively, current flow through the triac by shunting current from the one terminal of the power supply away from the triac gate and to the other power supply terminal, thereby providing control of the application of alternating current power to the apparatus.