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:
Dec. 05, 1989
Filed:
Aug. 08, 1988
Lloyd E Matthews, Berwyn, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
A compensation circuit for maintainng a CRT vertical raster size substantially constant with beam current changes includes a sensing resistor connected in series with the high voltage winding. The sensing resistor develops an input bias for a compensation transistor that has its output circuit connected across the vertical size control. Increases in beam current are reflected in increases in current in the high voltage winding which cause the compensation transistor to conduct more heavily and supply more current to the vertical size control. The size control is part of the discharge circuit of the vertical timing capacitor and the increased current from the transistor reduces the discharge time of the timing capacitor. Consequently the peak to peak voltage of the vertical current ramp is decreased.