Thanks to Hero for getting me this far!
I want to use the attached for a timer circuit, so far got most of the componants and hurdles as well as the rest of the (exterior to the timer) circuit sorted.
However....
I need to trigger (I think this is an edge trigger?) via loss of Vs (12v). Normally, the 12v will supplied. I want the timer to produce it's output once only when the 12v is cut. Note cut, it isn't switched to 0v, it's simply a loss of a Vs voltage to the trigger. Currently I think this circuit is set up to trigger via a 0v feed when I need it to trigger by loss of 12v (output on break).
Can anyone suggest a modification or direct me to a good web page on designing edge triggering?
Thanks, Greg.
I want to use the attached for a timer circuit, so far got most of the componants and hurdles as well as the rest of the (exterior to the timer) circuit sorted.
However....
I need to trigger (I think this is an edge trigger?) via loss of Vs (12v). Normally, the 12v will supplied. I want the timer to produce it's output once only when the 12v is cut. Note cut, it isn't switched to 0v, it's simply a loss of a Vs voltage to the trigger. Currently I think this circuit is set up to trigger via a 0v feed when I need it to trigger by loss of 12v (output on break).
Can anyone suggest a modification or direct me to a good web page on designing edge triggering?
Thanks, Greg.