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

On Thu, 29 Apr 2010 13:29:25 -0400, "Existential Angst"
wrote:

"Metspitzer" wrote in message
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On Thu, 29 Apr 2010 09:32:45 -0700 (PDT), Bob Villa
wrote:

On Apr 29, 9:07 am, 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?

You need a NC switch as you describe it.


Normally = Energized = most of the time.


Not in relays.


I meant De energized in motor relays and Energized in fire alarm
systems.