Power control circuit
AssigneeGeneral Motors Corporation
InventorDonovan L. Mock
Life of this patent
Estimating the term…
Abstract
A circuit connected to an AC source has first and second AC outlets for supplying power to first and second load devices. A control circuit response to power drawn from the first outlet controls power supplied to the second outlet such that the second outlet is energized only when current is flowing from the first outlet. Thus a record player or tape deck connected to the first outlet controls the supply of power to an amplifier connected to the second outlet.
Claims1
A power control circuit comprising, power supply conductors for connection to a source of alternating current, a first power outlet comprising first outlet terminals adapted to be connected to an electrical load, a transistor having collector, base and emitter electrodes, means connecting said first outlet terminals and the base and emitter electrodes of said transistor in series across said power supply conductors whereby base-emitter current is supplied to said transistor through said outlet terminals to bias said transistor conductive between collector and emitter when an electrical load connects said outlet terminals to provide a current path between said outlet terminals, said base-emitter current being comprised of first half cycles of alternating current supplied through said power supply conductor, a diode, means connecting said diode and said first outlet terminals in series across said power supply conductors, said diode connected across the base and emitter electrodes of said transistor and connected to provide second opposite half cycles of alternating current supplied by said source through said first outlet terminals when an electrical load is connected thereto, a second power outlet comprising second outlet terminals connectable to a second electrical load, a relay having a coil winding and contacts, means connecting said coil winding and the collector and emitter electrodes of said transistor across said power supply conductors, and means connecting said relay contacts in series with said second outlet terminals and across said power supply conductors whereby said second outlet terminals are energized from said source of alternating current when the power control circuit is connected to a said source of alternating current and said transistor is biased conductive by base-emitter current flow through said first pair of output terminals and whereby said second outlet terminals are disconnected from said source when said first outlet terminals are open-circuited to prevent transistor base-emiter current flow.
Dependencies are inferred from the claim text.