电荷克服导体电阻在闭合的回路中运动,推动这种运动的力量来源于相应的物理效应或化学效应,同时还伴随着能量的转换。电流在导体中流动时不停地消耗能量,但电路又及时补充了能量,这部分能量产生在被称为电源区的区域,我们用电动势来描述电源性质,电动势的本质是做功的物理过程。 The charge moves over the closed circuit against the resistance of the conductor, and the forces driving this movement come from the corresponding physical or chemical effects, accompanied by the conversion of energy. Current flow in the conductor constantly consume energy, but the circuit is promptly replenished energy, this part of the energy generated in the area known as the power area, we use the emf to describe the nature of the power, the nature of the emf is the physical process of doing work.