初学者电子教程，从易到难学的很透彻.建议刚刚入门的朋友看看....

代码说明：

初学者电子教程，从易到难学的很透彻.建议刚刚入门的朋友看看.-Electronic tutorials for beginners, from easy to difficult to learn very thorough. Recommendation of a friend just look at the entry.