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Electric blanket heating control with capacitance sensing

  • US 4,359,626 A
  • Filed: 09/19/1980
  • Issued: 11/16/1982
  • Est. Priority Date: 03/18/1980
  • Status: Expired due to Term
First Claim
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1. An electric blanket control for use with a blanket having an electrical heating circuit that includes an electrical resistance wire array in an expanse of blanket, the control effective to deactivate power to the heating circuit when the blanket is unattended, said control comprising means for applying electric power to said resistance wire array to generate heat in said expanse of blanket, a capacitance detector for said heating circuit, said capacitance detector being arranged for connection to said resistance wire array and constructed and adapted to respond to differences in the capacitance of the heating circuit attributable to the presence or absence of the user under the heating wire of the blanket, and switch means responsive to said capacitance detector adapted to interrupt power flow to said heating circuit when the capacitance value of the heating circuit indicates the absence of the user under the heating wire of the blanket.

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