《电子制作》96年第1期登载的《给3V收音机加装触摸开关》一文,作者只介绍了加装过程而未说电路工作原理,初学者可能不甚了解其工作原理,这里笔者补充其工作原理。如图所示,起初V1、V2无偏置电流而使V1、V2、V3、V4均截止。当手触摸到“开”时,V2基极为高电位V2饱和导通,并使V3饱和导通。R2上的压降大于0.3V时,V4管随之饱和导通, “Electronic production” 96, No. 1, “to 3V radio touch switch installed” article, the author only introduced the installation process without saying the circuit works, beginners may not understand how it works, where I added working principle. As shown in the figure, V1, V2, V3 and V4 are turned off at the beginning without V1 and V2 bias current. When the hand touches “on”, V2 base is high-voltage V2 saturated conduction, and V3 saturated conduction. When the voltage drop on R2 is greater than 0.3V, the V4 tube will saturate and turn on,