Electronic ballast with frequency control

  • US 5,757,140 A
  • Filed: 03/16/1992
  • Issued: 05/26/1998
  • Est. Priority Date: 03/20/1978
  • Status: Expired due to Term
First Claim
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1. An arrangement comprising:

  • a pair of power line terminals at which is provided a power line voltage;

    rectification and filtering circuitry connected with the power line terminals and operative to provide a DC supply voltage at a set of DC terminals;

    the absolute magnitude of the DC supply voltage being substantially constant; and

    inverter and load circuitry connected with the DC terminals and operative to provide an AC voltage at a pair of AC terminals with which is connected a gas discharge lamp;

    thereby to cause an alternating lamp current to flow through the lamp;

    the alternating lamp current having a peak magnitude and an RMS magnitude;

    the AC voltage being of a frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;

    the inverter and load circuitry being additionally characterized by causing the peak magnitude of the alternating lamp current to be distinctly lower than twice its RMS magnitude.

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