利用实验设备上8255扩展LED显示电路，A/D转换电路，完成类似恒温控制实验。其中利用数码管显示设定温度，利用可变电位器模仿温度变化，用ADC0809采样可变电位器的输出电压作为采样温度，将ADC0809采样到的温度以十六进制形式显示在屏幕上，并且与设定温度做比较，当采样温度超过设定温度时，启动制冷电机即亮红灯；当采样温度低于设定温度时，启动加热电机即亮绿灯。分别利用红、绿两只发光二极管发光表示制冷、加热电机工作。当采样温度等于设定温度时，红绿灯都不亮-8255 using experimental device extension LED display circuit, A/D converter circuit, completed a similar temperature control experiment. Which the use of digital display set temperature, the use of variable potentiometer mimic temperature changes, a variable potentiometer with ADC0809 samples the output voltage as the sample temperature, the temperature of the ADC0809 samples to be displayed in hexadecimal on the screen, and compared with the set temperature, when the sample temperature exceeds the set temperature, start cooling the motor that is red　when the sample temperature is below the set temperature, start heating the motor that green light. Respectively, using red, green light-emitting diode, said two refrigeration, heating electrical work. When the sample temperature is equal to the set temperature, the lights are not bright