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. 18, 2001
Filed:
Mar. 23, 1999
Applicant:
Inventor:
Douglas William Brooks, Carson City, NV (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H 3/18 ;
U.S. Cl.
CPC ...
H02H 3/18 ;
Abstract
Output protection for arc discharge lamp ballasts is provided by applying sampled ballast current to a burden capacitor selected to present a low impedance across the winding to a substantially symmetrical waveform of the sample current. Asymmetry between the positive and negative half-cycles of the sample waveform, such as partial rectification caused by abnormal lamp operation, results in charge buildup across the capacitor. Sufficient charge buildup actuates a ballast disabling switch such as a silicon controlled rectifier.