While resistors and capacitors often get the spotlight in beginner electronics, inductors are equally essential. These components are primarily used in AC circuits, especially in power supply and radio frequency 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 is essentially a coil of wire wrapped around a core, which may be air, iron, or ferrite.
How Inductors Work
When current flows through the coil, it generates a magnetic field. If the current changes, the magnetic field also changes, inducing a voltage according to Faraday’s Law. This induced voltage opposes the change in current, meaning inductors naturally resist sudden changes in current.
Types of Inductors
- Air-Core Inductors – used in high-frequency RF circuits.
- Iron-Core Inductors – provide high inductance but operate at lower frequencies.
- Ferrite-Core Inductors – commonly used in switch-mode power supplies.
- Toroidal Inductors – compact and efficient with minimal electromagnetic interference.
Key Parameters
- Inductance (H, mH, µH)
- DC Resistance (DCR) – resistance of the winding.
- Current Rating – maximum current the inductor can handle.
- Saturation Current – point where the core cannot store additional energy effectively.
- Self-Resonant Frequency – frequency where inductive and parasitic capacitive effects cancel out.
Applications
- Power Supply Filters – smooth ripple voltage.
- Chokes – block AC signals while allowing DC to pass.
- Transformers – enable voltage conversion.
- RF Tuned Circuits – used in radios and communication devices.
- Energy Storage – in switching regulators and buck converters.
Example: LC Filter in Power Supplies
In buck converters, inductors work with capacitors to regulate output voltage and current. They store energy during the switching cycle and release it gradually, helping maintain a stable output.
In Summary
Inductors may not always be highlighted, but they play a vital role in electronics. Their ability to store energy in a magnetic field and oppose rapid current changes makes them essential for power regulation, signal filtering, and RF applications.