Transistor Question !!

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Suraj143

Active Member

• Jul 22, 2010

• #1

Hi all I have a small problem !!

I have a NPN transistor.I'm turning ON this transistor by feeding logic 1 from a CMOS IC to the base.Now the transistor is ON.

Now I'm making that IC output to a high impedance state.Now what will be state of the transistor it it ON or OFF?

Thanks

 

MikeMl

Well-Known Member

Most Helpful Member

• Jul 22, 2010

• #2

Since it takes current injected into the base-emitter junction of an NPN to turn it on, and while the CMOS is in the high-Z state it can neither source, nor sink current, then the NPN will be off.

 

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Suraj143

Active Member

• Jul 22, 2010

• #3

Thanks Mike a clear reply.That's what I want to know.

 

A

ajsivsan

New Member

• Jul 23, 2010

• #4

I have a question in this. I connect the emitter to 5V. The collector is connected to 5V via a 1K ohm. I connect the load to the collector. I give voltage to the base via microcontroller. Now what will happen????

 

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Suraj143

Active Member

• Jul 23, 2010

• #5

It will do nothing.

 

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indulis

New Member

• Jul 23, 2010

• #6

Transistors can do funny things if the base/gate is left "floating".

 

Last edited: Jul 23, 2010