Jaws
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- Sep 26, 2008
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I want to add a PIR to an alarm system I have.. Only problem is all modern PIR's are supplied with 'normally closed' connections and I need one that is normally open.
Yes, I could use a relay but that would mean it would be held open all the time and draw current.. This is in a battery powered situation and the extra current draw would not be welcome !
So I got to thinking.. What about a thyristor ?
Only problem is, my bloody brain will not function and I am damned if I can figure out a way to use one ..
Basically I can hard wire either the +ve or -ve feed and have whichever is left going through the switched line.
I want it to have a feed to the -ve rail when there is no voltage applied to it..
So come on you clever buggers out there.. help !!!!
Yes, I could use a relay but that would mean it would be held open all the time and draw current.. This is in a battery powered situation and the extra current draw would not be welcome !
So I got to thinking.. What about a thyristor ?
Only problem is, my bloody brain will not function and I am damned if I can figure out a way to use one ..
Basically I can hard wire either the +ve or -ve feed and have whichever is left going through the switched line.
I want it to have a feed to the -ve rail when there is no voltage applied to it..
So come on you clever buggers out there.. help !!!!