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:
Feb. 03, 1987
Filed:
Apr. 22, 1985
Robert D Munson, Tupelo, MS (US);
Emerson Electric Co., St. Louis, MO (US);
Abstract
A solid state ballast for starting and operating a plurality of fluorescent lamps comprises a plurality of parallel connected, series LC circuits each coupled by a capacitor to a lamp so that voltage existing across the series capacitors is applied across the lamps and driven by an inverter at a DC power source voltage and at a selected frequency high enough to develop a lamp starting voltage but substantially below their resonant frequency. After starting the resonant frequency of the LC circuits is reduced substantially below the selected frequency by the added capacitive reactances of the coupling capacitors whereby the destructive high voltage at the upper and lower resonances is avoided and the independent selection of the values of L and C and the coupling capacitors to control starting voltage and conduction after starting at the selected frequency is provided.