controlling NPN transistors

Can an npn transistor be controlled with a ground rather than a voltage input? Like voltage at the base and a ground applied to the emitter allowing (that same ground) to be applied to another part of the circuit?

Not that i know of. That would be the job of a PNP transistor. If your circuit is digital, and you need to turn the transistor on with 0v, then just use an inverter connected to the base. (with a resistor, of course).

Someone correct me if i am wrong.

Also, there is absolutely no reason to double post.

strokedmaro said:

Can an npn transistor be controlled with a ground rather than a voltage input? Like voltage at the base and a ground applied to the emitter allowing (that same ground) to be applied to another part of the circuit?

Click to expand...

Yes, it's called the common base configuration.
Below is an example.

Fine. Then it can.