What Is Inductance?

An inductor is an electronic component made of coils. When current flows through a coil, a magnetic field is produced. The unit of inductance is the henry (H), named after Joseph Henry. One henry is the inductance that produces 1 volt of induced emf when current changes at 1 ampere per second. Inductors tend to block high-frequency signals while allowing low-frequency ones, opposite to capacitors; combining them enables frequency-selective circuits.

With integrated circuits, inductors are less common because 3D coils are hard to implement in 2D printed circuit boards. Designers often replace inductors with capacitors to achieve similar effects.