Four amplifiers Introduction
Time : 2016-12-02

bstract: Classification of amplifiers, amplifier described here in detail for your classification, B class amplifier, C, power amplifiers, D class amplifier, E power amplifier

1, B Class Amplifier

This type of amplifier for the 180° conduction angle efficiency of 78.5%, a half weeks of work. The use of superimposed positive and negative half-cycle approach can recover the input signal waveform. To compensate for superimposed voltage error caused by opening the tube, can be used to class AB.

2, C type power amplifier

In the high-power CW and FM output is widely used class C amplifier, the amplifier can change the AM offset adjustment to the changes. Knowledge described by the former, C, power amplifier turn-on angle is less than 180 °, non-linear output signal is not simply multiplying the input signal, A class amplifier with a tube, B class with two tubes, C, with a tube, just different bias points, B class amplifier output circuit filter can be improved by increasing the signal quality, C, the output circuit must have a resonant circuit to restore the fundamental signal, C class amplifier greatest advantage is efficiency.

3, D class amplifier

Class C power amplifier efficiency can reach 100%, but the output power is zero. Class B power amplifier bias change, making the output is not linear but non-linear half-cycle clipping, positive and negative square wave output, and then resumed after the resonant circuit sine, in the Class D amplifier, the tube close to the state in the switch. If the switching time is zero, the drain-source voltage is zero, the maximum leakage current is, in theory you can get 100% efficiency. In fact, BJT can work a few MHz, FET can work to tens of MHz, can not be infinitely fast.

4, E power amplifier

Switching power amplifier power amplifier can be described as above. In order to avoid the parallel capacitor discharge switching devices, switching instantly reduce power loss, you can load to the amplifier design of a network, decided to shut off, the voltage across the device, which is the Class E power amplifier.