Class C power amp

A power amps is reffered as class C if its o/p is obtained for less than a half cycle period of the i/p ac signal.

Thus power transistor in a class C configuration will conduct for a duration which is less than the period of half cycle of ac i/p signal.

• For this operating pt. is adjusted to be below X-axis. Thus transistors is biased below cut-off.
• Due to reduced conduction angle, the o/p waveform is heavily distorted. The percent distortion is higher than that for a class B amp. Therefore class C amps are not used A.F. power amps.

Advantages

i) Very high efficiency (higher than 95%)

ii) Low power loss in power transistor

Disadvantages

i) The waveform can be distorted.

Application

i) Class C amps generally use a tuned circuit as load. Such amps are called Class C tuned amps.

ii) These are used as the collector modulator to produce the amplitude modulated signal