通过开关或按键实现三个功能的切换：○1利用A/D转换芯片0809将W1电位器提供模拟量转换成数字量并显示；○2利用D/A转换芯片0832将单片机输出的数字量转换为模拟量输出并显示；○3利用W1电位器提供的模拟量经0809、单片机和0832转换和放大后驱动直流电机，实现电机调速。-Achieve three functions through the switch or button switch: ○ 1 use A/D converter chip 0809 will provide an analog potentiometer W1 converted into digital and display　○ 2 the D/A converter chip 0832 microcontroller output to digital conversion for analog output and display　○ 3 W1 use analog potentiometers provided by the 0809 microcontroller and 0832 conversion and amplified to drive DC motors, motor speed to achieve.