A circuit for a continuous running timer

Thread Starter

ulms

Joined Mar 19, 2024
50
Hello

I am needing a circuit to operate as follows. A maintained switch closure (the on signal) will initiate a high output for 15 seconds. Then the output should go low for 2 hours. I'd like it to run or cycle on 15 sec off 2 hours until the maintained switch signal is opened. Can anyone point me to a schematic for this?

Thanks
 

MisterBill2

Joined Jan 23, 2018
19,052
That should be created with two timers, and the price will depend on the accuracy required. OR it can be done with a rather inexpensive PLC and a bit of program. Are there any other functions in the same system that need to be controlled??
 

crutschow

Joined Mar 14, 2008
34,704
If you want to build one, here are two similar circuits that will generate the long interval.
The 15s pulse can be generated by a 555 one-shot, triggered by the long timer.
 
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