Inductors are passive components made by winding wire around a magnetic core or a hollow frame. Based on electromagnetic induction, they store energy in a magnetic field when current flows, and generate an induced emf when current changes. Inductance, measured in Henry (H) and its sub – units, gauges their opposition to current changes.
Inductors serve multiple key functions. In power and signal circuits, they filter out unwanted components. In power supplies, with capacitors, they form LC filters for stable DC output, like in computer power supplies. In signals, they help select frequencies, as in radio tuning. For energy storage, they buffer energy in DC – DC converters and create pulses in ignition systems. They also choke low – or high – frequency signals in relevant circuits. As transformers (a special type), they change voltage levels for power transmission and provide electrical isolation in safety – critical applications.