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’s essentially a coil of wire wrapped around a core, which could be air, iron, or ferrite.
The property that defines an inductor is inductance (L), measured in Henrys (H).
How Inductors Work
When current flows through the coil, it generates a magnetic field. When the current changes, the magnetic field changes too, which induces a voltage (as per Faraday’s Law) that opposes the change in current. This makes inductors resist sudden changes in current, making them ideal for smoothing or filtering applications.
Types of Inductors:
- Air-Core Inductors: Used in high-frequency applications like RF circuits.
- Iron-Core Inductors: High inductance, but limited frequency range.
- Ferrite-Core Inductors: Common in switch-mode power supplies.
- Toroidal Inductors: 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: When the core stops storing energy effectively.
- Self-Resonant Frequency: The frequency at which inductive and capacitive properties cancel out.
Applications:
- Power Supply Filters: Smooth out ripple voltage.
- Chokes: Block AC while passing DC.
- Transformers: For voltage conversion.
- RF Tuned Circuits: In radios and communication systems.
- 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 absorb energy during the ON period and release it during the OFF period, maintaining a consistent output.
In Summary
Inductors may not be flashy, but they are powerful. Their ability to store energy in a magnetic field and resist changes in current makes them critical for managing power and signal integrity. Whether you’re designing an amplifier, power supply, or RF system, understanding inductors is key to a well-functioning circuit.
