Based on NE555 this circuit turns on and off the IC output by a momentary switch. In other words it works as a mechanical latching relay, but the circuit backs to the start condition when you switch ...

This circuit allows an SPST momentary pushbutton to act as a push-on push-off switch, using a DPDT latching (bi-stable) relay. It was originally intended to allow a single pushbutton switch on the ...