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Electronics => Electronics => Topic started by: Tesla on May 30, 2009, 06:22:37 PM

Title: Normally Closed Transistor Help
Post by: Tesla 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

Title: Re: Normally Closed Transistor Help
Post by: Tesla 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?

Title: Re: Normally Closed Transistor Help
Post by: SmAsH 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?

Title: Re: Normally Closed Transistor Help
Post by: TrickyNekro 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

Title: Re: Normally Closed Transistor Help
Post by: Tesla on May 30, 2009, 08:15:41 PM

Thanks guys.. I figured it out!