方便电话灯张义方本文介绍的“方便电话灯”可以为夜间接电话和拿起听筒拨（按）电话号码时提供照明方便。电话铃响或拿起听简后，方便灯自动点亮；铃停或放下听筒时，方便何维持数秒后自熄。工作原理：电路如图所示。其中ＳＩ是与话筒钢联动的轻触开关，平时处在断位，拿... Convenient phone light Zhang Yi Fang This article describes the “convenient phone light” can pick up the phone for the night and pick up (press) the phone number to provide lighting convenience. After the phone rang or pick up Jane, convenient light automatically lit; bell stop or drop the handset, easy to maintain for a few seconds after the self-extinguishing. How it works: The circuit shown in the figure. Which SI is the touch switch with the microphone steel linkage, usually in the broken position, take ...