利用单片机AT89S51与ADC0809设计一个数字电压表，能够测量0－5V之间的直流电压值，四位数码显示，但要求使用的元器件数目最少-SCM AT89S51 ADC0809 design with a digital voltmeter to measure 0- 5V DC voltage between the value of four digital display, but requires a minimum number

基于pcf8591的ad转换器，实现的最大量程为5V的数字电压表，并附有仿真文件（需要安装proteous7.7）-The ad converter based pcf8591 to achieve the maximum range of 5V digital voltage meter, together with the simulation file (need to install proteous7.7)