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Sensitivity compensated fire detector

  • US 4,097,851 A
  • Filed: 07/19/1976
  • Issued: 06/27/1978
  • Est. Priority Date: 07/19/1976
  • Status: Expired due to Term
First Claim
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1. In a detecting device, a detector circuit having terminals for receiving a voltage thereacross and an impedance between said terminals which changes in value in accordance with the presence or absence of predetermined phenomena, for providing a first electric signal which changes relatively rapidly in value in response to the occurrence of said phenomena, means for generating in response to said first signal a second electric signal which changes in value in response to changes in value of said first signal, and means for monitoring the value of said second signal and for controlling said generating means to maintain said second signal at substantially a first predetermined value independent of said voltage across and impedance of said detector means for constant and relatively slowly changing values of said first signal, said second signal having at least a second predetermined value upon the occurrence of said phenomena.

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