I'd like to build a 12V one shot delay timer which would arm when the ignition key is turned "on" and start countdown (3-4 min) when key is turned OFF. So, the key OFF is a triggering event.
I found this circuit at http://home.cogeco.ca/~rpaisley4/LM555.html
and need help in determining values of C1,R1 to achieve 3-4 min delay or making it adjustable. Do I have the right circuit?
Power OFF Delay Circuits
These circuits will delay the removal of power to an external circuit by using mechanical relays or transistors. Other output control devices could also be used.
Thank you for your help
Manny
I found this circuit at http://home.cogeco.ca/~rpaisley4/LM555.html
and need help in determining values of C1,R1 to achieve 3-4 min delay or making it adjustable. Do I have the right circuit?
Power OFF Delay Circuits
These circuits will delay the removal of power to an external circuit by using mechanical relays or transistors. Other output control devices could also be used.
Thank you for your help
Manny
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