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metspitzer metspitzer is offline
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Default Define "Normally Open" vs. "Normally Closed"

On Thu, 29 Apr 2010 10:07:15 -0400, Bitzer wrote:

I'm replacing a broken surface mount magnetic switch mounted on my
garage door that controls a signal light in the house that comes on when
the door is open.

Thus, I need a switch that is OPEN (meaning no current flows) when the
magnet is near the switch and CLOSED (meaning current flows) when the
magnet is removed from the switch.

So do I need a normally open switch or a normally closed one? Different
manufacturers/vendors seem to use the terms differently. Is it "normal"
when the magnet is near the switch-- or away from it?


Or you can look at the switch you pulled out and wire the new one the
same way.