Re: class c
an amplifier is said to operate in class c when an output signal is produced for less than 180 degree of the input signal. as we progress from the letters A,B,AB,C,D,G the amount of time for which load current is produced reduces.
in class A the output signal is produced for the whole input signal. this type has the least efficiency. in class B the output is generated for 180 degrees of the input signal. class B improves the efficiency but the tradeoff is that u get a highly distorted signal (one that has half the signal clipped :!: ). so as u progress through the letters the efficiency increases and the distortion increases too.
class c amplifiers are used for high power applications (communication). class c is used because of its high efficiency. we dont care about the distortion it produces because the output of the class c amplifier is not the information we are transmitting. its the carrier signal that carries the information.
i hope that helps