Possible Duplicate:
I don't care how a transistor works, how do I get one to work?
Basic questions about transistor amplification

I have heard transistors are used in many electronic devices to amplify current such as in microphones which amplify the sound. I want to know how do they what do they do? How can a transistor just amplify electric current from nothing?


Transistor needs a power source, it can't amplify a signal "from nothing".

You ask the very basics. I think you should read the first chapter of some book. For example Principles of Transistor Circuits.

Or at least Wikipedia article on transistor.


Not the answer you're looking for? Browse other questions tagged or ask your own question.