说明：  在单片机开发中常用信号转换电路，此压缩包含电压转化电流，电流变电压的转换电路，在单片机开发过程中是非常有借鉴意义的，与大家共享
(Commonly used in the development of single-chip signal conversion circuit, the compressed packet contains the voltage into current, variable voltage current conversion circuit, in the single-chip development process is very meaningful reference, and share)