Simple 555 timer circuit needed.

AI Thread Summary
A user is seeking a simple LM555 timer circuit that activates after a switch is held down for one second, essentially a reverse of typical monostable circuits. They are looking for guidance on how to achieve this functionality, including using a push button on the trigger pin to initiate the cycle. Suggestions include utilizing a dual 555 timer (the 556 chip) to create a delay before pin 3 goes high if the switch remains depressed. The user is confident in handling the circuit reset but needs assistance with the initial setup. Overall, the discussion focuses on creating a delay mechanism using the LM555 timer.
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Hi all, great forum here. Hope to learn a lot.

I am looking for a sample LM555 circuit. In simple terms I am looking what I think to be a reverse of the monostable circuits I have seen.

More or less I have a switch that needs to be held down for 1 sec before the circuit is active (pin 3 high on the LM555). Or is there another circuit? I think the 555 would do what I need, just need a sample circuit to bump me in the right direction.

Reseting the circuit I think I can handle, but just need a simple circuit to get me there.

Any help would be greatly appreciated.
 
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You could put a push button on the trigger pin to signal a start of a cycle.
 
triden said:
You could put a push button on the trigger pin to signal a start of a cycle.

That is sort of what I a doing now. The switch needs to be held down for one second and then before pin 3 goes high.

If that makes better sense.
 
You might want to check into the 556 chip. It's a dual 555 timer. See if you can use one to trigger the other after 3 seconds if the switch is still depressed.
 
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