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FIRE AND BURGLAR ALARM SYSTEM

  • US 3,686,668 A
  • Filed: 03/04/1970
  • Issued: 08/22/1972
  • Est. Priority Date: 03/04/1970
  • Status: Expired due to Term
First Claim
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1. In a burglar alarm system for providing an alarm in response to the detection of an unauthorized entry of a building, said system comprising alarm generating means, control circuit means including a control relay operable when energized to effect energization of said alarm generating means to provide an alarm, said control relay having a winding with first and second ends, means for connecting the first end of said winding to a point of energizing potential, current rectifier means and indicator means connected in a series circuit path between the second end of said winding and a point of reference potential for providing an energizing path for said control relay, and entry switch means having a normally closed switch connected between said current rectifier means and said point of energizing potential for extending said energizing potential to said current rectifier means to reverse bias said current rectifier means whenever said switch is unoperated to thereby interrupt said energizing path, said switch being operated in response to an unauthorized entry of said building to enable the second end of the winding of said control relay to be connected to the point of reference potential over said series circuit path whereby said control relay is operated to affect energization of said alarm generating means.

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