原因之一发生短路是电路中电流过大的主要原因之一．照明电路的线路中火线与零线在某处直接相通构成回路，就发生了短路．造成保险丝熔断.解析当电路中某处短路，线路中的电阻Ｒ会变得很小，而电压Ｕ仍保持一定，根据欧姆定律。Ｉ＝Ｕ／Ｒ，通过保险丝的电流强度Ｉ就剧增，又根 One of the reasons is that the occurrence of a short circuit is one of the main causes of excessive current in the circuit. In the circuit of the lighting circuit, the fire line and the zero line are directly connected to each other to form a loop, and a short circuit occurs. Causes the fuse to blow. Analyze When somewhere in the circuit is short-circuited, the resistance R in the line becomes very small, and the voltage U remains constant, according to Ohm’s law. I=U/R, the current intensity I through the fuse increases sharply, again