2款简单而经典的麦克（驻极体话筒）放大电路，一款采用三极管，一款采用tda2822功放芯片。可用于设计扩音器的前端电路。-2 simple and classic Mike (electret microphone) amplifier circuit, using a transistor, a use tda2822 amplifier chip. Can be used for front-end circuit design loudspeakers.