PROTECTOR FOR POWER SUPPLY AND PROTECTIVE DEVICE FOR POWER SUPPLY CIRCUIT

摘要

PROBLEM TO BE SOLVED: To downsize a deterioration display circuit and further surely check performance of a varistor in a protector for power supply at a time of maintenance.;SOLUTION: The protector for the power supply comprises: the varistor 46 that is connected between power source terminals 41 and 42; a fuse 45 that is connected with the varistor 46 in series; and the deterioration display circuit 50 that is connected with the varistor 46 in parallel and displays a deterioration state of the varistor 46. The deterioration display circuit 50 has an LED 52 that puts the light on when a driving current is supplied through the fuse 45, and puts the light off when the fuse 45 burns and thereby the supply of the driving current is stopped; a diode 53 that is connected with the LED 52 in a reverse polarity direction in parallel; a capacitor 51 for limiting a current, which is connected with the LED 52 in series; and a resistor 54 for limiting a current, which is connected with the LED 52 and the capacitor 51 in series.;COPYRIGHT: (C)2013,JPO&INPIT