CLASS AB AMPLIFIERS
so that collector current
is zero (cutoff) for
portion of one alternation of the input signal. Therefore, collector current will
flow for more than 180 degrees but less than 360 degrees of the input signal.
The class AB amplifier is commonly used as a push-pull amplifier to overcome
a side effect of class B operations.
CLASS B AMPLIFIERS - biased so that collector current is cut off during one-
half of the input signal. So, for a class B operation, collector current will flow
for approximately 180 degrees (halt) of the input signal. The class B operated
amplifier is used as an audio amplifier and sometimes as the driver- and
CLASS C AMPLIFIERS
so that collector current flows for less than one-
half cycle of the input signal. The class C operated amplifier is used as a RF
FIDELITY AND EFFICIENCY - two terms used in conjunction with amplifiers.
Fidelity is the faithful reproduction of a signal while efficiency is the ratio of
output signal power compared to the total input power. The class A amplifier
has the highest degree of fidelity, but the class C amplifier has the highest
23 June 2005