自动量程档电压表。共三个档位0-0.1,0.1-1,1-10.可根据输入电压的大小自动切换档位。由51单片机控制。-Autoranging voltmeter. A total of three stalls 0-0.1,0.1-1,1-10. Automatically switch gear according to the size of the input voltage. Controlled by the microcontroller 51.