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Lighting system having photosensing timing switch circuit

  • US 4,851,738 A
  • Filed: 02/24/1987
  • Issued: 07/25/1989
  • Est. Priority Date: 08/11/1982
  • Status: Expired due to Term
First Claim
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1. A controlled lighting system comprising at least one lighting apparatus set for illuminating a given area;

  • means for supplying power to the at least one lighting apparatus set;

    control circuit means for controllably coupling the means for supplying power to said at least one lighting apparatus set, said control circuit means including light sensing means responsive to ambient light for developing a control signal whenever intensity of ambient light reaches a given level and remains at that level or becomes less;

    delay circuit means coupled to said light sensing means and responsive to the control signal therefrom for developing a delayed control signal indicating that the intensity of ambient light has remained at or below said given level for at least a given time interval, making the system nonresponsive to short term ambient light intensity variations;

    pulse-producing timing circuit means coupled to said delay circuit means and responsive to the delayed control signal therefrom for providing output pulses for a predetermined time interval;

    step switch means for switching ON and OFF power to the at least one lighting apparatus, said step switch means being coupled between the means for supplying power and the at least one lighting apparatus set;

    means coupled to said pulse-producing timing circuit means and responsive to output pulses therefrom for advancing said step switch means in step fashion for a given time interval during which power is ON and upon the expiration of which the step switch means switches OFF power from said means for supplying power to the at least one lighting apparatus set; and

    means for resetting said step switch means upon expiration a further time interval and exposure of the light sensing means to light.

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