Amplification
In the case of
amplification the transistor is used to amplify a signal. One
example of such a signal can be a sound. To the left is an
example of a circuit that is used to amplify sound signals.
The sound entering the microphone is converted to an
electrical signal that is amplified in the transistor. This
amplified sound signal then travels through the circuit until
it reaches the loudspeaker. This speaker converts the
electrical sound signal back into a sound. The sound leaving
the speaker is the same as the sound that entered the
microphone, only much louder. This is called amplification
– the sound is being amplified.