Avoid dead zone voltage. The A and B power amplifiers are biased statically to avoid the dead-time voltage region, so that each transistor is in a micro-conduction state. Once the input signal is added, it will immediately enter the linear operating region, which can give the complementary transistor a static bias. Class A power amplifier has full static bias. In order to overcome crossover distortion, Class B power amplifier has no static bias, so it is difficult to overcome crossover distortion.