Rca Inc.

George C Waybright

Donald Henry Willis

Peter E Haferl

Ronald E Fernsler

David W Luz

Hugh F Sutherland, Ii

James A McDonald

A degaussing circuit for a video display apparatus eliminates residual degaussing current flow during operation of the video display apparatus. A capacitor is connected between coil of the degaussing relay and the source of energizing voltage. Application of the energizing voltage to the relay coil energizes the relay and initiates degaussing of the cathode ray tube of the video display apparatus, and also causes the capacitor to begin charging. As the capacitor becomes charged, the degaussing relay becomes deenergized, thereby terminating degaussing current flow. The capacitor charging time constant is selected to allow sufficient time for degaussing to occur before deenergization of the degaussing relay.

Degaussing circuit with residual current cutoff

Line and field deflection circuits generate line and field deflection currents in respective line and field deflection windings to scan a raster on the phosphor screen of a square-planar picture tube having an aspherical faceplate. The asphericity of the faceplate subjects the scanned raster to gullwing distortion. A gullwing distortion correction circuit is responsive to signals repeating at line and field rates, respectively, for modulating the field deflection current during a line deflection period within the field deflection trace interval in a manner that corrects gullwing distortion of a corresponding raster scan line.

Gullwing distortion corrected deflection circuitry for a square-planar

A high voltage generator of a television receiver is responsive to an alternating voltage, such as a retrace pulse voltage, and develops an ultor voltage at an ultor terminal. A high voltage protection circuit includes a comparator that, when activated, disables normal television display. A sense voltage representative of the ultor voltage is coupled to an input terminal of the comparator so as to activate the comparator when the ultor voltage exceeds a predetermined threshold level. A sense voltage representative of the ultor beam current is also coupled to an input terminal of the comparator so as to vary the threshold ultor voltage level at which the comparator is activated in accordance with beam current variations. When the ultor beam current exceeds a level indicative of high voltage generator overload, a switch that is coupled to an input terminal of the comparator changes states to activate the comparator and shut down the high voltage generator.

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Carmel, IN, United States of America

George C Waybright