| 摘要 |
PURPOSE:To prevent the breakdown of the horizontal output transistor by flowing once the collector current to the horizontal output transistor after start of operation of the X-ray leak prevention circuit and then inhibiting the operation of the X-ray leak prevention circuit in the horizontal pulse period via protective circuit. CONSTITUTION:X-ray leak prevention circuit 11 detects the fluctuation of the high voltage applied to the anode of the CRT, and the output is inhibited from horizontal output circuit 5 when the detection voltage exceeds the fixed level. The collector current is flown once to horizontal output transistor Tr4 after the operation of circuit 11 is started, and thus the operation of circuit 11 is inhibited via protective circuit 17 for the horizontal pulse period and regardless of the level of the detection voltage. Thus, the breakdown of the horizontal output Tr can be prevented. |
