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Ballast power control circuit

  • US 6,181,082 B1
  • Filed: 10/15/1998
  • Issued: 01/30/2001
  • Est. Priority Date: 10/15/1998
  • Status: Expired due to Fees
First Claim
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1. A ballast circuit for energizing a lamp, comprising:

  • first and second input terminals for receiving an AC input signal which energizes the ballast circuit;

    an inductive element coupled to the first input terminal;

    a plurality of capacitive elements coupled in parallel with the lamp, each of the capacitive elements having first and second terminals, said first terminal being coupled to the inductive element, wherein a current flowing through the capacitive element and the inductive element resonates in series, a switch connected to said capacitive elements and configured to selectively couple different selected ones of said capacitive elements into said ballast circuit to selectively vary the total capacitance of said ballast circuit.

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