| 摘要 |
PURPOSE:To avoid the variation of the size of a horizontal screen which is caused according to the level of the beam current, by controlling the voltage which is applied to a flyback transformer of a horizontal output circuit in accordance with the level of the beam current of a TV picture tube. CONSTITUTION:A horizontal output circuit 1 is a known circuit which receives the electric power from a power supply circuit 2 via a control circuit 3 and the primary winding L2 of a flyback transformer T1 and drives a horizontal deflecting coil L1. For the circuit 3, a diode D3 and a resistance R2 are newly provided between a horizontal ripple smoothing capacitor C3 and a power supply ripple smoothing capacitor C4. The diode D3 and the resistance R2 control the voltage at a joint 4, i.e., the voltage applied to the transformer T1 in accordance with the variation of the anode current which is supplied to a picture tube via the secondary winding L3 of the transformer T1. Thus the size of a horizontal screen is kept constant. |
