How does an Inductor Store Energy?

An overview of inductors

An inductor is a device for inducing a time-varying electric current in a conductor. An inductor is similar to a resistor since it resists the passage of electric current. However, whereas resistance is due to electrons colliding with atoms or other electrons in the conductor, an inductor’s properties arise from its ability to store energy as a magnetic field. This self-inductance arises because electrically charged particles that pass near the surface of the conductor create electrical currents within the conductor according to Faraday’s law of induction. These time-varying currents produce a magnetic field that acts as an electrical current in the wire itself.

An inductor is usually a coil or helix of wire surrounding a core and operates as an effective electromagnet when an electric current flows through the conductor. The magnetic flux linking the turns (or “windings”) induces a voltage in each turn by Faraday’s law of induction. An inductor is characterized by its inductance, which is the ratio of an applied voltage to the induced electromotive force (i.e., V/L, where L is the inductance in henrys).

How does the inductor store energy?

An inductor stores energy in the creation of a magnetic field. An inductor is a device consisting of a coil of insulated wire usually wound around a magnetic core—most often iron. Current flowing through the wire generates an electromotive force that acts on the following current and opposes its change in value. Like all components that store electrical energy, an inductor has an “inductive reactance”, which opposes changes in current. The inductive reactance depends on the self-inductance, the rate at which the magnetic field in an inductor is changing, and on how long it is exposed to that field change.


The potential energy stored in a suitably configured inductor is proportional to the integrated electromotive force and to the time integral of voltage. The magnetic field presented by the inductor is proportional to the current and to the rate of change of current times time plus an additional term which does not depend on current, but only on voltage. For this reason, electrical power can be obtained from such a device. This power is proportional to the rate at which the current changes and to the self-inductance of the device, which depends on its construction and size.

Applications of inductors

An inductor is a passive electrical component typically used to provide a standardized impedance and voltage drop while blocking direct current. It is a coil of wire that functions by storing energy in the magnetic field created by the electric current passing through it. Inductors are often used with alternating current circuits because they can convert electrical power efficiently from one form to another. In an alternating current circuit, an inductor will cause an electric current on the opposite side of its coil from the applied electric current’s direction of flow to have a greater phase delay than the phase of the electrical current passing through it.

Inductors are not just for use in electronics. You can find inductors in the following areas:

  • Magnetron lifters on construction sites
  • Driving motors on washing machines
  • Trailers that are connected to cars by a trailer hitch
  • Aeroplane wings that are used to enhance their stability
  • Pulse forming networks allow the voltage to rise rapidly at first, then fall more slowly later on.


I hope this article has helped provide some insight and guidance on the way the inductors store energy in order to improve your life. Easybom has also provided detailed information about SMD inductors.