An inductor (also choke, coil or reactor) is a passive two-terminal electrical component that stores energy in its magnetic field. For comparison, a capacitor stores energy in an electric field, and a resistor does not store energy but rather dissipates energy as heat.
Any conductor has inductance. An inductor is typically made of a wire or other conductor wound into a coil, to increase the magnetic field.
When the current flowing through an inductor changes, a time-varying magnetic field is created inside the coil, and a voltage is induced, according to Faraday's law of electromagnetic induction, which by Lenz's law opposes the change in current that created it. Inductors are one of the basic components used in electronics where current and voltage change with time, due to the ability of inductors to delay and reshape alternating currents.
Read more about Inductor: Overview, Applications, Inductor Construction, In Electric Circuits, Q Factor, Inductance Formulae