本次设计用单片机芯片AT89s52设计一个数字万用表，能够测量交、直流电压值、直流电流、直流电阻，四位数码显示。此系统由分流电阻、分压电阻、51单片机最小系统、显示部分、报警部分、AD转换和控制部分组成。-The design of MCU chip AT89s52 to design a digital multimeter, capable of measuring AC, DC voltage, DC current, DC resistance, four digital display. The system consists of a shunt resistance, pressure resistance, 51 MCU minimum system, display, alarm, AD conversion and control part.