How does an inductor work in an electrical circuit?

An inductor in an electrical circuit stores energy in a magnetic field when electric current passes through it.

An inductor, also known as a coil or a reactor, is a passive two-terminal electrical component. It's designed to resist changes in electric current that pass through it. It does this by storing energy in a magnetic field. The ability of an inductor to store energy in its magnetic field is known as inductance, which is measured in units called henries (H).

The principle of operation of an inductor is based on Faraday's law of electromagnetic induction. This law states that a change in the magnetic field within a loop of wire induces an electromotive force (EMF) in the wire. In simpler terms, when the current flowing through an inductor changes, the magnetic field created by the inductor also changes. This changing magnetic field induces a voltage in the inductor that opposes the change in current. This is why inductors are said to 'oppose changes in current'.

In a direct current (DC) circuit, an inductor acts like a short circuit after the magnetic field is fully established. This means that it allows the DC to flow through it without any resistance. However, in an alternating current (AC) circuit, an inductor behaves differently. It opposes the AC by creating a phase difference between the voltage and the current. This is known as inductive reactance, and it increases with the frequency of the AC.

In practical applications, inductors are used in a variety of ways. They're often found in electrical transmission systems, where they're used to limit the change of current over time and to filter out certain frequencies. They're also used in electronic devices like radios and televisions to tune into specific frequencies. Understanding how an inductor works is crucial to understanding many aspects of electricity and electronics.