| 摘要 |
PURPOSE:To prevent a zooming phenomenon without using a high voltage regulator and to reduce the over scanning amount of a beam by varying vertical deflection current in accordance with the increase/decrease of anode voltage. CONSTITUTION:A high voltage generation circuit 1 supplying anode voltage HV to the anode of CRT and a vertical deflection circuit A supplying vertical deflection current to a vertical deflection coil 15 are provided, and a correction power source part 16 obtaining low voltage proportional to the increase/decrease of anode voltage HV is provided. In the vertical deflection circuit A, a vertical driving part 8 amplifies voltage which a vertical oscillation part 7 outputs by a prescribed gain, the output voltage e0 fluctuates in proportion to low voltage which the correction power source part 16 generates and the vertical deflection coil 15 is driven based on output voltage e0. Thus, vertical deflection current changes in proportion to anode voltage HV. When the circuit gain of the vertical driving part 8 is set to a desired value, the picture size of the beam can be held constant in spite of anode voltage HV. |
