# Explanation for transistor as amplifier

In transistor as an amplifier, we have NPN transistor (base in the middle and emitter and collector at the sides). The collector has electrons in majority because it is N-type. similarly, holes are in majority in base, but as it is lightly doped, it has very little amount of hole. Now, when a small signal of alternating current is supplied to the base, the base current changes and this change is called input current. most of this input current moves into the collector (base has less holes so most of the current moves on when it fills the holes). Now, the collector has its own majority charge carriers (electrons) and some more electrons are added to it by the input signal. So when collector gives current to the load, it will be the combination of input signal and the already present electrons. Hence, small signal is amplified.

Am I right or wrong?

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Shouldn't this be in electronics.stackexchange.com ? –  Garan Jan 23 '13 at 8:46
@Garan this question is about the physics of an electronic device and is OK here. –  Larry Harson Jan 25 '13 at 17:25
Cross-posted from electronics.stackexchange.com/q/55791 after 4 minutes. –  Qmechanic Mar 8 '13 at 0:22
Dear Muhammad Rafique. In general, it is frown upon to cross-post simultaneously, because it may waste potential answerer's time. As a minimum OP should mention the cross-post (on both sites!). The preferable procedure is not to crosspost, and if the post hasn't received an acceptable answer after, say, a couple of days, then OP could flag for migration. –  Qmechanic Mar 8 '13 at 0:37