我们知道电路的状态有三种:通路、开路和短路.对于短路,可以分为整体短路和局部短路.课本上通常讲,所谓“短路”就是直接把导线接在电源上(即电流没有经过用电器而直接构成通路),这时电路中会有很大的电流,可能把电源烧坏.这是不允许的,这种短路称为整体短路. We know that there are three kinds of circuit state: access, open circuit and short circuit. For short circuit, it can be divided into overall short circuit and partial short circuit. In the textbook, generally speaking, the so-called “short circuit” is to directly connect the wire to the power supply (ie, the current is not passed through the power supply. And directly constitute the path), then there will be a large current in the circuit, the power may be burned out. This is not allowed, this short circuit is called the overall short circuit.