| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent explosion and firing of a varistor due to a short circuit current in a short circuit failure state of the varistor, and to suppress damages of a protection target device even when power is supplied again in the short circuit failure state. <P>SOLUTION: An electronic device including a surge protective element includes a fuse 102, the protection target device 107 protected from excessive surge and a varistor 106 for absorbing the excessive surge, has exciting coil incorporating type interruption means 104 comprising a switch 111 provided in a power supply line and an exciting coil 110 for turning it off, and is provided with a temperature switch 105 thermally coupled to the varistor 106, and a series connection circuit of the exciting coil 110 and the temperature switch 105 is connected to the power supply line. When the varistor 106 fails in a short circuit state, the temperature switch 105 detects heat generation by the varistor 106 and performs an off operation, the switch 111 is cut off and the power supply line is disconnected. When power is supplied again by an on operation of the switch 111 during the short circuit state failure of the varistor, the power supply line is disconnected again by heat generation detection by the temperature switch 105. <P>COPYRIGHT: (C)2013,JPO&INPIT |
