说明：  本电路所选用的是AT89C2051可编程的高性能小型单片机。AT89C2051内含有Flash存储器，所以可反复使用。用AT89C2051开发电子制作，安全性高，制作简单，调试方便，功能多样，容易调动起学生的兴趣，开发学生动手动脑的积极性。
(Chosen in this circuit is a a small microcontroller AT89C2051 programmable high-performance. The AT89C2051 contains Flash memory, and so can be used repeatedly. With the the AT89C2051 development of electronic production, high security, making a simple, convenient debugging, versatile, easy to arouse the interest of the students, and the development of the enthusiasm of the students hands-on brain.)