There are no principle diagrams of a direct electric circuit, and circuit design has to look for several related material, and debugs a program, and fixes the last circuitry.

• 而电路设计没有直接的电路原理图，需要查找一些相关的资料，然后进行调试，确定最终电路图。该题目是设计类题目，所以相对制作麻烦些。该电路可以实现三种信号对同一个LED的控制。