An inductor is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. It is also known as a coil, choke, or reactor. Inductors are typically used as energy storage devices in switched-mode power devices to produce DC current. They are used extensively in analog circuits and signal processing, ranging from the use of large inductors in power supplies to the small inductance of the ferrite bead or torus installed around a cable to prevent radio frequency interference from being transmitted down the wire.
Inductors resist changes in current, and when the current changes, a voltage is created across the inductor’s terminals that opposes this change. Any wire with current flowing through it has a small magnetic field surrounding it. When you wind the wire into a coil, the field becomes stronger. If you wind the wire around a magnetic core, such as steel or iron, you’ll get an even stronger magnetic field. This is how you create an electromagnet. Inductors have the following specific application purposes:
- Dividing necessary signals and unnecessary signals (filtering)
- Preventing sudden changes in current used
Inductors are not as commonly used in beginner circuits, but they are very common in power supplies, such as to create a buck or boost converter.
