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AUTOMATIC TEMPERATURE CONTROL DEVICE FOR ELECTRIC BLANKET

  • US 3,564,203 A
  • Filed: 06/04/1969
  • Issued: 02/16/1971
  • Est. Priority Date: 06/05/1968
  • Status: Expired due to Term
First Claim
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1. An automatic temperature control device for use with an electric blanket, comprising a heating wire, a heat-sensitive layer formed over the entire length of said heating wire and consisting of a flexible solid organic material having a negative resistance temperature coefficient and adapted to become conductive to such an extent as to pass a current sufficient to cause a controlling action when heated to a certain temperature or higher, a signal wire provided opposite to said heating wire with said heat-sensitive layer intervening therebetween, a relay for operating a make-and-break contact connected in series with said heating wire, a transistor for actuating said relay, and an input and output resistors and a rectifier for said transistor, said transistor having the collector thereof connected to one end of the output resistor through the relay and the emitter thereof connected with the other end of said output resistor and the base thereof connected to the connection between said relay and said output resistor through a series circuit consisting Of said signal wire and said input resistor, and said output resistor being connected to a power source through said rectifier.

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