n Amplifiers are electronic circuits that are used ot increase the amplitude of an electronic signal.

n The primary use of the transistor - studied earlier - is as an amplifying device

n There are four types of amplifiers in common use. They are biased so that the output current flows as indicated

        ð Class A:  Throughout the cycle

       ð Class AB: More than half of the input cycle but less than the full cycle

       ð Class B:  Half of the input cycle

       ð Class C: Less than half of the input cycle