Hitachi, Ltd.

Tsueno Fujikura

Takeo Yamada

Masanori Ogino

Miyuki Ikeda

Takahiko Fujiwara

A video output circuit for driving a CRT of a grid-cathode differential drive type is disclosed, in which a collector potential of an output transistor in a horizontal blanking interval is detected by a diode arrangement; the potential thus detected is smoothed by a smoothing filtering arrangement output current of the output transistor is controlled by an output obtained by the smoothing filtering arrangement; and negative feedback control is effected so that the collector potential of the output transistor is made constant. In this way, a bias adjusting power supply, which was required heretofore, is made unnecessary.

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Yokohama, Japan

Tsueno Fujikura