Author Topic: Normally Closed Transistor Help  (Read 4112 times)

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Offline TeslaTopic starter

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Normally Closed Transistor Help
« on: May 30, 2009, 06:22:37 PM »
Hi all,

I need help with a circuit that gives me a 5v (high) when a normally closed circuit is opened.  How do I configure the transistor and is it PNP or NPN.

Thanks,
Jason
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Offline TeslaTopic starter

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Re: Normally Closed Transistor Help
« Reply #1 on: May 30, 2009, 07:06:14 PM »
I have thought about it.. if I use a PNP and keep base high and then when open base is low, the current will flow E to C... correct?
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Offline SmAsH

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Re: Normally Closed Transistor Help
« Reply #2 on: May 30, 2009, 07:20:22 PM »
what is the transistor connected to?
you could use a no relay so when the circuit opens it closes the switch?
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Offline TrickyNekro

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Re: Normally Closed Transistor Help
« Reply #3 on: May 30, 2009, 07:51:21 PM »
In PNP it's Collector high rail, Emitter device
In NPN it's Emitter low rail, Collector device...
Check this out
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Offline TeslaTopic starter

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Re: Normally Closed Transistor Help
« Reply #4 on: May 30, 2009, 08:15:41 PM »
Thanks guys.. I figured it out!
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