JPS5791030A - Off-delay timer - Google Patents

Abstract

PURPOSE:To prevent the generation of chattering even if a power supply is applied again in any timing, by inhibiting the excitation of a set coil when a reset coil is excited and releasing the inhibition of excitation of the set coil after the end of reset operation. CONSTITUTION:When a power supply E is applied, a time limit operation is stopped through the operation of a switching element Q2 of a power failiure detection circut 5. In a set coil driving circuit 2, a current flows to a gate circuit of a switching element S1 through a resistor R21, the element S1 turns on and a set coil KS of a latching relay K is excited. Thus, a contact K2 of the relay K of a set inhibition circuit 3 turns on to charge a capacitor C2 of a reset coil driving circuit 4, and a switching element Q1 is turned on via a resistor R23 of a circuit 3, and since the gate of the element S1 is shortened, the element S1 turns off at the bottom of the waveform of power supply in full-wave rectification. Thus, the time limit operation of a timer circuit 6 is stopped through the circuit 5.