本报告介绍了基于AT89S52单片机为核心的、以AD0809数模转换芯片采样、以1602液晶屏显示的具有电压测量功能的具有一定精度的数字电压表。在实现基础功能要求之上扩展了串口通讯、时钟功能、高压报警、短路测试、电阻测量、交流电压峰峰值和周期测试等功能，使系统达到了良好的设计效果和要求。-This report describes the AT89S52 microcontroller based on the core to AD0809 DAC chip sampling to the LCD screen display 1602 voltage measurement function with a certain precision digital voltmeter. On the basis of functional requirements in the realization of extension of the serial communication, clock function, high-pressure alarm, short-circuit test, resistance measurement, AC voltage peak and the cycle of testing and other functions, allowing the system to achieve a good design effects and requirements.