Inductors are circuit components that generate electromotive force due to changes in the current passing through them, thereby resisting changes in current. The structure of an inductor is similar to that of a transformer, but with only one winding. It is generally composed of a skeleton, winding, shielding cover, packaging material, magnetic core or iron core, etc.
If an inductor is in a state where no current passes through, it will attempt to obstruct the current from flowing through it when the circuit is turned on; If an inductor is in a state where current is passing through, it will attempt to maintain a constant current when the circuit is disconnected.