I have built this circuit and need to modify it to fit my situation. In my circumstance the button in the pic is a relay contact and is held until the output signal goes low. The result of the circuit the way it is now in operation is that the relay flips on the circuit 555 output goes high and after the period (decided by time constant RC) the circuit goes low and the relay flips off (turned off by controller) . That's exactly what i need but after some time the relay flips back on and the output of the 555 never goes hi again.

http://555-timer.clarkson-uk.com/operation/mono4.html

Any ideas...??

Thanks
pete

 

You will need a debounce circuit if the relay is anything but a reed relay. You also need to add a pullup to the relay/switch contact like this:

Attached Images

monoa.gif (4.4 KB, 9 views)

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