Inductor
Understanding inductors, their types, and applications.
What is an Inductor?
An inductor is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. It typically consists of a coil of wire. When current changes through an inductor, it creates a voltage that opposes the change in current, a property known as inductance.
How Inductors Work
Inductors resist changes in current. When current flows through a coil, it generates a magnetic field. If the current increases, the magnetic field expands, inducing a voltage that opposes the increase. If the current decreases, the magnetic field collapses, inducing a voltage that opposes the decrease, trying to maintain the current flow.
Types of Inductors
| Type | Description | Common Applications |
|---|---|---|
| Air-Core Inductors | No magnetic core, low inductance, high frequency. | RF circuits, high-frequency filters. |
| Iron-Core Inductors | Iron core, high inductance, low frequency. | Power supplies, audio frequency circuits. |
| Ferrite-Core Inductors | Ferrite core, good for high frequencies, reduces eddy currents. | Switching power supplies, RF chokes, EMI filters. |
| Toroidal Inductors | Doughnut-shaped core, self-shielding, efficient. | Power converters, medical devices, telecommunications. |
| Variable Inductors | Adjustable inductance. | Tuning circuits, oscillators. |
Applications of Inductors
- Filters: Used in conjunction with capacitors to filter out unwanted frequencies.
- Chokes: Block AC signals while allowing DC to pass.
- Energy Storage: Store energy in switching power supplies.
- Tuning Circuits: Used in radio and TV tuners to select specific frequencies.
- Transformers: Two or more inductors coupled by a magnetic field to transfer energy between circuits.
Frequently Asked Questions
What is the difference between an inductor and a resistor?
A resistor opposes current flow and dissipates energy as heat. An inductor opposes changes in current and stores energy in a magnetic field.
Can inductors be connected in series or parallel?
Yes. For inductors in series, total inductance adds up (L_total = L1 + L2 + ...). For inductors in parallel, the reciprocal of total inductance adds up (1/L_total = 1/L1 + 1/L2 + ...), similar to resistors.