Hitachi, Ltd.

Mitsuharu Akatsu

Tadashi Nagasaki

Takesuke Maruyama

Shuzo Matsumoto

Masao Obara

Ichiro Niitsu

Ryoichi Hirota

Gentaro Miyazaki

Mitsuo Otsu

Mitsuo Ohtsu

A high voltage generating apparatus suitable for a television receiver. A flyback transformer has a secondary winding divided into a plurality of parts by at least a diode and a primary winding connected to a variable voltage divider circuit for varying the primary-side flyback pulse voltage. The variable voltage divider circuit is connected to an end of a focus capacitor with the other end thereof connected to the cathode of the diode, so that a variable pulse voltage is applied to the focus capacitor to regulate the focus voltage.

High voltage generating apparatus

A signal having a maximum amplitude corresponding to a pedestal level of a composite video signal is produced by removing a horizontal synchronizing signal from the composite video signal. An automatic gain control signal is derived from the first mentioned signal in dependence of the peak value thereof to control a high frequency amplifier and or an intermediate frequency amplifier so that the pedestal portion at the maximum amplitude level of the composite video signal is maintained constant. In this way, a stabilized pedestal portion or the black level can be attained, which in turn results in a stabilized contrast.

Automatic gain control circuit

A high voltage generator suitable for use in a television receiver set wherein a frequency dependent attenuation circuit is connected to a primary winding of a flyback transformer which generates a high voltage to be supplied to a CRT whereby a regulation for a high voltage is improved.

High voltage generator

The present invention relates to a deflection yoke device which is preferably combined with an in-line type color picture tube having electron guns aligned horizontally. The distribution of magnetic fields is determined in the horizontal direction such that a sharp or strong barrel magnetic field is localized on the side of the neck portion whereas an extremely sharp pincushion magnetic field is localized on the side of the funnel portion and at the same time, an intensely sharp pincushion magnetic field is distributed between the funnel portion and the neck portion. The central electron beam is deflected more at a greater angle than side electron beams so as to land outside the side electron beams.

Deflection yoke device for use in color television receiver sets

A high voltage regulating circuit has a cathode-ray tube, horizontal deflection means comprising a horizontal deflection output transistor and a horizontal deflection coil for generating a saw-tooth current therein, high voltage generating means connected with the anode of the cathode-ray tube for supplying a high D.C. voltage to the anode thereof and comprising a high voltage generating output transistor, a flyback transformer and a high voltage rectifier, a voltage source, a variable impedance means connected between the voltage source and the high voltage generating means, and a control signal supply means. The control signal is supplied to the impedance means to control the impedance thereof so as to control the voltage supplied to the high voltage generating means thereby maintaining constant the high D.C. voltage supplied to the anode of the cathode-ray tube.

Growing community of inventors

Yokohama, Japan

Mitsuharu Akatsu