本文介绍一种基于AT89S51单片机的智能型数字式多用表,该系统采用MC14433——3 1/2位A/D转换器和LED数码显示，可以测量直流电压、交流电压、直流电流和电阻，并且具有键盘选择测量对象、量程和自动量程转换功能。-This paper presents a AT89S51 MCU-based intelligent digital multimeter, the system uses the MC14433- 3 1/2 bit A/D converter and LED digital display, can measure DC voltage, AC voltage, DC current and resistance, and has a keyboard to choose measurement object, measurement range and automatic range conversion functions.