Short circuit: the neutral line and live wire in the line are accidentally connected together during electrician operation, and the line is partially short-circuited (short circuit means that the effective resistance in the line is zero. Will trip or blow the fuse). If it is not handled in time or improperly, it may lead to damage of lines (including electronic components), and in serious cases, it may lead to electric shock, fire or personal electric shock injury.
Under certain circumstances, we will deliberately short-circuit to achieve our goal. For example, in physical experiments, we often short-circuit a circuit, find the circuit fault in sections, and also need to short-circuit to zero when using the ohm file of multimeter.