| 摘要 |
PURPOSE:To attain stable focus adjustment by superimposing a DC being the result of rectifying an AC extracted from a tap provided at a part of the secondary side winding of a flyback transformer onto the secondary winding of the flyback transformer via an adjusting resistor. CONSTITUTION:An A.C. extracted by providing a tap to the secondary winding L2 of the flyback transformer (FBTR) 12 is fed to a rectifier circuit via a capacitor C3. The rectifier circuit consists of diodes D2, D3 and a capacitor C4, the output voltage is fed to the 2nd grid G2 of a CRT 10 and an output voltage adjusted by a variable resistor R1 provided to an output terminal is superimposed on the secondary winding L2 of the FBTR 12 to adjust the output voltage VA of a rectifier circuit Recf thereby controlling the anode voltage of the CRT 10. Thus, stable focus adjustment is applied by a simple circuit. |
