transistor

is transistor used as amplifier?

is transistor used as amplifier?

It's November now. Two months into class and you still don't know?

What do you find when you Google "transistor amplifier"?

Yes. The npn transistor uses ideas that are very smart. The grounded emitter is silicon doped with arsenic with high concentraction and the next silicon section , base, is oppositely doped with boron to make a pn diode with the emitter. When a diode is forward biased, mobile carriers flow with an advantageous amount ratio : the p base sends fewer positive holes into the emitter than the n emitter sends electrons into the base. Amplification is explained in those two flows : few holes from the base create a large flow of electrons from the emitter. So a small base current is amplified into a large electron current : AMPLIFICATION ! The collector is lightly doped and electrons fromthe emitter diffuse into the collector after crossing the thin base. This collection allow "charge neutrality" to continue for years, if the temperature remains below 125 degrees celsius. If the transistor gets too hot several failure mechanisms destroy this amplifired.

Google on transistor wiki

The first sentence says:" A transistor is a semiconductor device used to amplify and switch electronic signals and power".

In fact it is a current amplifier.

That depends on the type of transistor and also on the circuit topology.

Yes, it's a "current amplifier," which, depending on the circuit configuration, can make a voltage amplifier, a current amplifier (either of which could be described as "electronic signals") and/or a power amplifier.

And don't forget, that's Wiki, not Elementary Electronics 101. ;-)

Hope This Helps! Rich