I am replacing an older timer, actually two, with newer digital ones. I picked a couple up from Home Depot and flipped the circuit breaker and went to town. Upon pulling the old timers out I see one ...

The above circuit uses a 555 timer U1 in mono stable mode. If once push button is pressed, it drives pin2 of timer momentarily to ground that triggers the 555 to deliver a high output at pin 3 to ...