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Filment switch for a lamp ballast

  • US 5,132,595 A
  • Filed: 06/21/1990
  • Issued: 07/21/1992
  • Est. Priority Date: 06/21/1990
  • Status: Expired due to Term
First Claim
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1. A switching circuit for a rapid start type fluorescent lamp having a filament operating from a ballast transformer which supplies voltage to the filament and operating voltage to the lamp comprising a triggered switch in series with a lamp filament, voltage sensitive means connected to sense the voltage across the lamp, the triggered switch being connected to the voltage sensitive means and operated by the voltage sensitive means so that the triggered switch is on and the filament is supplied voltage from the ballast when the lamp arc is not struck and is essentially off when the voltage across the lamp drops after the lamp arc is struck to remove the voltage to the filament.

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