earphone 专八

1.An operator wearing earphone was sitting in the telephone exchange.

戴机的接线员正坐在总机室里。

2.The Capacitor turns the signal in antiphrasis, the only thing whole. The Earphones do such long ago. The Shot of the handgun not audible.

什么是积极保护？基本原理是：发射和接收信号---放大，晶体管---可变电阻的电容---扬声或射极的输出装置。