The ideal transistor will not consume power because there is no saturation voltage drop

The ideal transistor will not consume power because there is no saturation voltage drop. In fact, the transistor will always have small saturation voltage drop consumes local electric energy. This kind of power consumption is only related to the characteristics of the tube, and is independent of the size of the signal output, so it is particularly beneficial to the occasion of super power. Under ideal conditions, 100% efficiency, Class B power amplifier efficiency class D power amplifier
The efficiency of Class A power amplifier is only 50% or 25% (depending on the load mode)
In fact, it only has the switch function, and was only used in the switch control circuit of relay, motor and other actuating elements in the early days
Class D power amplifier however, the switching function (that is, the function of generating digital signals) is used to the road of Hi Fi audio amplification is increasingly smooth. In the 1960s, designers began to study for audio class D power amplifier
Bose Company began to produce Class D automotive power amplifiers in the 1970s
To achieve higher efficiency, on the other hand, the space is too small to fit a power amplifier with a large heat sink structure. Both hope to have Class D an efficient amplifier is used to amplify the audio signal. The key step is to modulate the audio signal