| 摘要 |
PURPOSE:To prevent the destruction of a horizontal output transistor, by detecting the presence of an input to a horizontal driving circuit, and actuating a high voltage protecting circuit while a horizontal driving transistor is turned off. CONSTITUTION:For a horizontal deflecting circuit of a TV picture receiver, the output terminal of a horizontal oscillating circuit 13 is connected to the base terminal of a horizontal driving transistor TR16 via a current limiting resistance 15 as well as to the base terminal of a timing TR32 via a resistance 31. The emitter of the TR32 is grounded with its emitter connected to the gate of an SCR28. When the TR16 is turned on, the TR32 is also turned on. Then the abnormal voltage pulse flows to the TR32 from the tertiary coil of a flyback transformer via a diode 26 and a Zener diode 27. Thus the operation of the SCR28 is prevented. |
