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:
Sep. 28, 1976
Filed:
Nov. 24, 1975
Peter Adrian Dear, London, EN;
Wladyslaw Pelc, London, EN;
Thorn Electrical Industries Limited, London, EN;
Abstract
A ballast circuit for a discharge lamp uses simply a capacitor in series with a relatively small inductor the capacitative reactance being between 24 and 55 times the inductive reactance. At these values the third harmonic distortion is unexpectedly low, while the crest factor (ratio of peak to r.m.s. current) is still within acceptance values. Because the inductor is small the efficiency of the circuit is high, and its cost and weight reduced. The capacitance/inductance ratio can be equated to the ratio of the frequency of the tuned circuit to the supply frequency, and on this basis the preferred range is defined by 5 to 71/2 times supply frequency.