| 摘要 |
PURPOSE:To prevent production of an X-ray by interrupting an AC power switch based on a fault discrimination of a high frequency transformer output voltage by a level discrimination means so as to stop the operation of a high frequency transformer surely. CONSTITUTION:A high frequency output current at a terminal 7x of a secondary winding of a high frequency transformer 7 is rectified and given to an X-ray protection circuit 22 via a point P. The input voltage is monitored and when it exceeds a prescribed voltage, an oscillation stop signal is fed to a horizontal oscillation circuit 5. On the other hand, a level discrimination means of a CPU 10 detects a voltage received by an X-ray protection input port 10x to discriminate the threshold level. If the voltage is higher than a prescribed threshold value, it is discriminated that an abnormal voltage is generated and the CPU 10 provides an output of a signal to switch off a power switch to the X-ray protection output port 10y. An OFF circuit 14 goes to an L level based on a level output and an electromagnetic relay 13 is driven to interrupt the AC power input switch 2. |
