What is an inductor? Use of Inductors

In this articles I will explain to you what is inductor which is another important component in the field of electrical and electronics.

An inductor is a passive two terminal point component that temporarily stores energy in the form of a magnetic field. It is usually seen in the form of a coil. The property of an inductor is its ability to resist any change in current.

What is an inductor? Use of Inductors


Faraday's law of electromagnetic induction states that when the current flowing through an inductor changes, the time-varying magnetic field induces a voltage across the conductor. Lenz's law states that the direction of the induced emf opposes the change in the current it has created. Hence, the induced emf will be opposite to the voltage applied across the coil. This is a property of an inductor.

A passive electronic component capable of storing electrical energy in the form of magnetic energy is known as an inductor. Basically, it uses a ferrite core inside its conducting coil. When current is passed through the inductor coil from left to right, the inductor creates a magnetic field in a clockwise direction.

Some of the purposes of using inductors in applications are;
  • Separation of required signals and unwanted signals (filtering).
  • Stabilization (smoothing) of voltage in a power circuit. 
  • Creating matching resistance in high frequency circuit.

Energy storage of inductor

One of the fundamental properties of electromagnetism is that, when current flows through an inductor, a magnetic field is created perpendicular to the current. It stabilizes at one point, which means no inductance is built up thereafter. When the electric current stops, the magnetic field gradually decreases.

The excess energy is temporarily stored in the form of a magnetic field. So this magnetic energy is converted into electrical energy and flows out.

Working of an inductor

According to the theory of electromagnetic induction, any varying current flowing in a conductor produces a magnetic field around it, which is perpendicular to the current. Also, any varying magnetic field produces current in the conductor in that field, provided the current is perpendicular to the magnetic field.

The parameter that indicates the quality of an inductor is called Q value. "Q" stands for "quality". Because direct current passes easily through the coils, but also acts as a resistance to alternating current, this characteristic is called inductive reactance. As the frequency of the current increases, the inductive reactance increases.

Quality factor of inductor

Since each inductor has a small resistance in addition to its inductance, the value of this resistance R decreases and the quality of the coil improves due to this. An inductor quality factor, or Q factor, the operating frequency is defined as the ratio of the reactance of the coil to its resistance.

Inductor Formula

Although the coil is a conductor, its wire winding has some resistance factor (R). The ratio between resistance factors and frequency-dependent inductance (R/2πf L) is called loss factor and its inverse number is called Q value (Q=2πf L/R). Since 'f' is the frequency of the current flowing through the coil, the Q value varies with frequency. Simply put, a higher Q value means less loss and better suitability for use as a high frequency inductor.

Q = 2πf L/R 
Q = Quality, π= 3.14, f= Frequency, L= Length, R= Resistance

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