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Alarm device

  • US 4,174,516 A
  • Filed: 12/05/1977
  • Issued: 11/13/1979
  • Est. Priority Date: 12/05/1977
  • Status: Expired due to Term
First Claim
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1. An alarm device for use in conjunction with automobiles having electrical systems, said alarm device comprising:

  • (a) electric power connection means for connecting the device to the automobile electrical system;

    (b) a first trigger means operably connected to the electrical power means, said first trigger means responsive to voltage variations and capable of producing electrical signal in response to such voltage variations;

    (c) square wave generating means for converting electrical signal of the first trigger means into a square wave signal, said square wave generating means electrically connected to the first trigger means;

    (d) siren means for sounding a siren in response to said activating means and electrically connected to said activating means, said siren means having;

    a first operational amplifier circuit including an inverting and non-inverting input, and an output;

    a second operational amplifier circuit including an inverting and non-inverting input, and an output;

    a first transistor having a base, emitter, and collector, said first transistor electrically connected between said first operational amplifier circuit and said second operational amplifier circuit;

    and positive voltage biasing means for positively biasing the non-inverting inputs of said first and second operational circuits, wherein the output of said first operational amplifier circuit is connected to the base of said first transistor, and the collector of said first transistor is connected to the inverting input of said second operational amplifier circuit;

    (e) activating means responsive to the square wave signal for activating said siren means, said activating means electrically connected between said square wave means and said siren means;

    (f) arming means for arming and dearming said first trigger means, and operably connected to said first trigger means;

    (g) a first timing means for deactivating said siren means at some preset period beyond the time when said siren means is activated, said first timing means electrically connected to the siren means;

    (h) a second timing means providing a delay time interval between the time when the arming means is activated, said second timing means electrically connected to the first trigger means; and

    (i) a third timing means providing a delay interval between the time said activating means produces an activating signal and the time set siren means is activated, said third timing means electrically connected to the activating means.

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