以STC12C5052AD单片机&LCD1602实现一个单闭环直流电机调压调速控制，用键盘实现对直流电机的起/停、正/反转控制，速度既可用键盘数字量设定也可用电位器连续调节-To STC12C5052AD SCM & LCD1602 achieve a single-voltage closed-loop DC motor speed control, using the keyboard to achieve the effe

基于Keil C51的晶体管测试仪（改为其他型号的单片机很容易，关键是STC12C5052AD比较便宜），里面的特征测试要用到AD转换，功能：基本晶体管引脚识别，hFE，二极管引脚识别，PN及NP压降，单向可控硅引脚识别，触发电压及维持偏压测试。-Based on Keil C51 transistor tester (to other types of microcontrollers is easy, the key is STC1

STC12C5052AD做的智能充电器，冲两节1.2V充电电池，（没电池会快速闪烁，充电过程两个LED交替闪，充满绿灯常亮）充满自停（充满电为常数可在原代码里调整MAX_VALUE）。-STC12C5052AD do smart charger, washed two 1.2V rechargeable batteries (no battery will flash quickly, charging two alternately

测二极管（包括稳压二极管，发光二极管），三极管（NPN，PNP型自动识别），可控硅等晶体管的极性自动识别，导通压降及hFE等等特性。-Measuring diode (including the zener diode, light emitting diode), triode (NPN and PNP type automatic recognition), silicon controlled transistor, such a