说明：  PC数字电压表的设计,原理图以及代码,设计文档.此数字电压表的优势在于可以通过串口将测量所得到的电压值传给PC机,这样的话有利用整个数据的采集与分析.上位机采取的是串口通信软件.
(PC digital voltage meter design, diagram and code, Design Documentation. This figure voltage meter advantage is through the serial port will be measured by the voltage transmission PC, so is the use of the entire data collection and analysis. PC's serial port communication software.)