×

Auxiliary lighting system for a gaseous discharge lamp

  • US 3,873,882 A
  • Filed: 10/05/1973
  • Issued: 03/25/1975
  • Est. Priority Date: 10/05/1973
  • Status: Expired due to Term
First Claim
Patent Images

1. An auxilairy lighting system for use with a primary lighting system having a gaseous discharge lamp and a ballast connecting the gaseous discharge lamp to an alternating current source of voltage for igniting and operating said gaseous discharge lamp, said auxiliary lighting system comprising:

  • a. an auxiliary light source;

    b. switch means connected in series with said auxiliary light source and an output from a ballast;

    c. said switch means comprising an SCR and a bridge rectifier;

    d. biasing means connected in series with said switch means and said auxiliary light source for producing an output voltage acting on said switch means and maintaining said switch means in a conductive condition;

    e. said biasing means including a resistor connected between a gate electrode of said SCR and a source of positive voltage; and

    f. control means responsive to a voltage across the discharge lamp for producing an output proportional to said lamp voltage and opposing the output voltage of the biasing means;

    g. said control means includes a transformer and a rectifier connected across a gaseous discharge lamp for Producing a negative output voltage proportional to the voltage applied to said discharge lamp;

    h. said output voltage from the transformer and rectifier being connected to the gate electrode of the SCR;

    i. said control means having an output voltage which is greater in magnitude than said output voltage from the biasing means during a period of time when said gaseous discharge lamp is operating at full illumination and said SCR is in a nonconductive condition, and causing said SCR to become conductive in response to application of a starting voltage to said gaseous discharge lamp;

    j. said control means also including a filter circuit and a breakdown device connected between the output of the transformer and the rectifier and the gate electrode of the SCR;

    k. said breakdown device producing a fixed low voltage after application of a high voltage thereto in response to the application of a starting voltage to the discharge lamp.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×