SWITCHING CONDITION MONITORING CIRCUIT AND SWITCH

PROBLEM TO BE SOLVED: To provide a switching condition monitoring circuit, capable of efficiently executing the monitoring with a high reliability in case of constantly monitoring the on/off condition of a switch. SOLUTION: This switching condition monitoring circuit monitors the on/off condition of a switch SW to be monitored, on the basis of whether the microcurrent I0 flows to a node N via a current-limiting resistor R0. This circuit has a current supply circuit 30, having a capacitor C1 and a discharge limiting resistor R2, and the electric charge charged in the capacitor C1 under a off- condition of the switch SW, is rapidly discharged through the discharge limiting resistor R2 and the switch SW in accompany with the switching-on of the switch SW. Here, a large amount of the electric current, in comparison with the microcurrent 20, is supplied instantaneously to the switch SW, so that an oxide film on a switch contact can be attempted to be eliminated, even when it exists.