| 摘要 |
PROBLEM TO BE SOLVED: To provide an over-voltage protection circuit which can safely cut off a circuit when an over-voltage is generated in the AC power supply. SOLUTION: In a circuit, a first fuse, a line filter and a rush current preventing resistor are connected between an AC power supply and a rectifying/ smoothing circuit, and an over-voltage protection element is connected in parallel to a smoothing capacitor of the rectifying/smoothing circuit. A second fuse is connected between a rectifying bridge diode of the rectifying/smoothing circuit and the over-voltage protection element, a first diode is connected between the over-voltage protection element and smoothing capacitor, and moreover a second diode is connected respectively to the second fuse and first diode. Moreover, the cathode (anode) of the first diode and the anode (cathode) of the second diode are connected to the anode side (cathode side) of the smoothing capacitor, and the cathode (anode) of the second diode is connected to the second fuse and the rectifying bridge diode.
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