Introduction

When you open up an electronic circuit board, you’ll see tiny components, resistors, capacitors, transistors, and one more crucial part: the inductor. Though often overlooked compared to capacitors or resistors, inductors play a key role in shaping how current flows in circuits.

In this article, we’ll break down what an inductor is, how it works, the different types available, and where you’ll find them in real-world applications.


Inductor (Electronic Component): Definition, Working, Types, and Applications


What is an Inductor?

An inductor is a passive electronic component that stores energy in the form of a magnetic field when an electric current passes through it. It usually looks like a coil of wire wound around a core (air, iron, or ferrite).

Symbol in circuit diagrams: A series of loops or coils.

Unit of measurement: Henry (H).


Symbol and unit of Inductor

In simple terms, inductors resist changes in current. This property makes them essential in filtering, tuning, and energy storage applications.


Working Principle of an Inductor

The operation of an inductor is based on Faraday’s Law of Electromagnetic Induction:

  • When current flows through the coil, it generates a magnetic field around it.

  • If the current changes, the magnetic field also changes, inducing a voltage that opposes the change in current (known as self-inductance).

This opposition helps smooth out fluctuations in circuits, which is why inductors are commonly found in power supplies and filters.


Key Properties of Inductors

1. Inductance (L) – The ability to store magnetic energy, measured in Henry (H).

2. Current Handling – Maximum current the coil can handle without overheating.

3. Core Material – Air core, iron core, or ferrite core, each affecting efficiency.

4. Resistance (DCR) – The natural resistance of the wire used in the coil.


Types of Inductors

1. Air Core Inductors

  • No magnetic material, just a coil of wire.

  • High-frequency applications like RF circuits.

2. Iron Core Inductors

  • Coil wound around an iron core.

  • High inductance, suitable for low-frequency applications.

3. Ferrite Core Inductors

  • Core made of ferrite material.

  • Widely used in power electronics and high-frequency circuits.

4. Toroidal Inductors

  • Donut-shaped core.

  • Compact, efficient, and reduces electromagnetic interference (EMI).

5. Variable Inductors

  • Inductance can be adjusted.

  • Useful in tuning radios and communication devices.


Applications of Inductors

Inductors are everywhere in electronics. Some common uses include:

1. Power Supplies

  • Filtering out AC ripple in DC supplies.

2. Transformers

  • Inductors are the basic building blocks of transformers.

3. Radio Frequency Circuits

  • Used for tuning and signal processing.

4. Energy Storage

  • Inductors temporarily store energy in their magnetic field.

5. Filters

  • Combined with capacitors to create low-pass, high-pass, and band-pass filters.

6. Motors and Relays

  • Inductor coils are used to generate magnetic fields for mechanical movement.


Advantages of Inductors

  • Simple and reliable component.

  • Excellent at filtering unwanted signals.

  • Can handle high current without large voltage drops.


Limitations of Inductors

  • Bulky compared to capacitors and resistors.

  • It can be expensive, especially for high-value inductors.

  • Energy losses due to resistance and core heating.


Inductor vs Capacitor

Feature Inductor Capacitor
Stores energy in Magnetic field Electric field
Opposes Change in current Change in voltage
Unit Henry (H) Farad (F)
Common symbol Coiled wire/series of loops Two parallel plates
Typical uses Filters, chokes, transformers, and energy storage in power electronics Coupling/decoupling, timing, energy storage, filters
Frequency behavior Impedance increases with frequency (XL = 2Ï€fL) Impedance decreases with frequency (XC = 1/(2Ï€fC))
Losses Resistive (DCR) and core losses (hysteresis, eddy currents) Dielectric losses and equivalent series resistance (ESR)
Size vs value Higher inductance is often larger or requires a magnetic core High capacitance can be compact (electrolytic), but voltage/ESR trade-offs apply
Polarity Non-polar (but orientation matters in coupled inductors/transformers) Some types are polar (electrolytic); most ceramic/film are non-polar
Typical failure modes Overheating, shorted turns, core saturation Dielectric breakdown, increased ESR, leakage


Conclusion

The inductor may not get the spotlight like transistors or ICs, but it’s a fundamental building block of electronics. From power supplies to radios, communication devices to transformers, inductors quietly ensure smooth operation by controlling current and storing energy.

Understanding how inductors work and where they’re used is essential for anyone diving into electronics, whether you’re a student, hobbyist, or professional engineer.