The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 13, 1995
Filed:
Dec. 22, 1993
John K Moriarty, Jr, Reading, PA (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
A gas-discharge lighting system having an inductor and at least two capacitors in combination with a gas discharge lamp, the inductor and capacitors forming a resonant system, the resonant frequency thereof being dependent upon whether the lamp is nonionized or ionized. The lamp is operated by driving the lamp, inductor, and capacitor combination with a signal of a first polarity and inverting the polarity when the signal current transitions a predetermined current level. This repeated until the polarity of the signal remains of one polarity longer than a predetermined time, at which time the signal is inverted. This is repeated indefinitely. The predetermined length of time is one-half the inverse of a minimum frequency greater than the ionized resonant frequency. To protect the lighting system from overload, if the signal current exceeds a predetermined level, then the polarity of the signal is inverted, effectively moving the frequency of the signal up away from the ionized resonant frequency, thereby reducing the power delivered to the lamp. This method is applicable to fluorescence lighting and other gas-discharge lamps, such as mercury and sodium vapor lamps.