AT89X52两点间温度控制 用可调电阻调节电压值作为模拟温度的输入量，当温度低于30℃时，发出长嘀报警声和光报警，当温度高于60℃时，发出短嘀报警声和光报警。测量的温度范围在0－99℃。 -AT89X52 between two resistance temperature control with adjustable voltage regulator as the input analog temperature, when the temperature is below 30 ℃, the issue of long嘀alarm sound and light alarm, when the temperature is higher than 60 ℃, issued a short sound and light alarm嘀alarm. Measurement of the temperature range of 0-99 ℃.