An Inductor is a passive electronic component that stores energy in the form of a magnetic field when current flows through it. It usually consists of a coil of wire wound around a core (air, iron, or ferrite). 🔹 Working Principle When current flows through the coil, it creates a magnetic field. If the current changes, the magnetic field also changes, which induces a voltage (called back EMF) that opposes the change in current (as per Lenz’s Law). The ability of an inductor to oppose changes in current is measured in Henrys (H). 🔹 Key Properties Inductance (L): Measure of how much magnetic flux is generated per unit current. Unit: Henry (H). Reactance (XL): Opposition to AC current flow, 𝑋 𝐿 = 2 𝜋 𝑓 𝐿 X L ​ =2πfL (depends on frequency). DC Behavior: Acts like a short circuit (only wire resistance). AC Behavior: Opposes current changes (higher opposition at higher frequencies). 🔹 Types of Inductors Air Core Inductor – coil without core (low inductance, used at high frequencies). Iron Core Inductor – coil wound on iron core (higher inductance, power applications). Ferrite Core Inductor – widely used in RF circuits, filters, and SMPS. Toroidal Inductor – coil wound on a ring-shaped core (compact, high efficiency). Variable Inductor – inductance can be adjusted. 🔹 Applications Power Supplies – as filters to smooth AC to DC conversion. Transformers – coupling AC signals between circuits. Radio & Communication Circuits – tuning circuits (resonance with capacitors). Energy Storage – in SMPS, DC-DC converters. Chokes – block high-frequency noise while allowing DC/low frequency. Motors & Relays – electromagnetic operation. 🔹 Advantages Efficient for filtering and energy storage. Simple, passive component with no power requirement. Can handle high currents in power circuits.