The general principles of power amplifiers
How a generic amplifier works
Figure 3.1 shows a very conventional power amplifier circuit; it is as standard as possible. A great deal has been written about this configuration, though the subtlety and quiet effectiveness of the topology are usually overlooked, and the explanation below therefore touches on several aspects that seem to be almost unknown. The circuit has the merit of being docile enough to be made into a functioning amplifier by someone who has only the sketchiest of notions as to how it works.
The input differential pair implements one of the few forms of distortion cancellation that can be relied upon to work reliably without adjustment -this is because the transconductance of the ...