Inductors 101: Function, Types, and Real-World Applications

Inductors are essential passive components found in power supplies, communication devices, filters, and many other electronic systems. Although they may look simple—usually just coils of wire—their behavior is fundamental to controlling current, managing energy, and shaping electrical signals.

This article explains what inductors are, how they work, the main types used in modern electronics, and where you will typically find them.

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1. What Is an Inductor?

An inductor is a passive electronic component that stores energy in a magnetic field when current flows through it. It is typically made from a coil of insulated wire wound around a core, which may be air, ferrite, iron, or other magnetic materials.

The ability of an inductor to store energy is measured in henries (H). In practical circuits, most inductors have values ranging from microhenries (µH) to millihenries (mH).

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2. How Does an Inductor Work?

When current passes through the wire coil of an inductor, it creates a magnetic field around the coil. The inductor resists any change in current, meaning:
• If current tries to increase suddenly, the inductor opposes the increase.
• If current tries to decrease suddenly, the inductor releases stored energy to keep current flowing.

This behavior makes inductors especially useful in circuits that deal with energy transfer, filtering, or current regulation.

Key characteristics of inductors include:
• They oppose sudden changes in current.
• They store energy in a magnetic field.
• Their performance depends on the core material, coil turns, and physical structure.

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3. Common Types of Inductors

Inductors come in many forms, each suited to specific applications.

Air-Core Inductors

These inductors use air as the core. Without a magnetic material, they avoid saturation and distortion, making them ideal for high-frequency applications such as RF circuits.

Ferrite-Core Inductors

Ferrite cores increase inductance and efficiency. They are widely used in power supplies, filters, and switching regulators because ferrite materials handle high frequencies well and reduce losses.

Iron-Core Inductors

Iron cores provide high inductance and support high current, although they work better at lower frequencies. These inductors are often found in audio equipment, transformers, and industrial power circuits.

Toroidal Inductors

Toroidal inductors are shaped like rings. Their closed magnetic path reduces electromagnetic interference and improves efficiency. They are common in power converters and EMI filters.

SMD (Surface-Mount) Inductors

Designed for compact electronics, these inductors are optimized for automated production and appear in smartphones, laptops, and IoT devices. They are available in many sizes and inductance values.

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4. Key Functions of Inductors in Circuits

Inductors serve essential roles in both power and signal circuits.

Energy Storage

Inductors temporarily store energy in their magnetic field, which is particularly important in switching power supplies.

Filtering

Paired with capacitors, inductors help remove noise and ripple from power lines, stabilizing output voltage.

Boost and Buck Conversion

Inductors are key components in DC-DC converters, enabling voltage step-up and step-down operations.

Chokes

Inductors used as chokes block high-frequency noise while allowing DC or low-frequency signals to pass. This is essential in power supplies and communication circuits.

Tuning and Resonance

In RF circuits, inductors form resonant circuits with capacitors to select or filter specific frequencies, such as in radios and wireless systems.

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5. Where Are Inductors Used?

Inductors are used across a wide range of industries and applications, including:
• Switching power supplies and DC-DC converters
• Mobile phones, tablets, and laptops
• LED drivers and backlighting circuits
• Automotive electronics and EV power systems
• Communication devices, including radios and wireless modules
• Industrial equipment and motor control systems
• Medical electronics and instrumentation
• Noise filtering and EMI suppression in all types of devices

Wherever energy must be stored, noise must be filtered, or current must be controlled, inductors play a critical role.

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6. Final Thoughts

Inductors may appear simple, but they are essential to modern electronics. By resisting changes in current and storing energy in magnetic fields, they enable stable power delivery, clean signals, and efficient energy conversion.
Understanding inductor types and their applications helps engineers, buyers, and manufacturers make better decisions when selecting components for a project.