Calculate inductance, inductive reactance, RL time constant, stored energy, and series/parallel combinations. Animated magnetic field visualization with full unit conversions.
Inductors store energy in a magnetic field when current flows through them. They are essential in power supplies (filtering), radio circuits (tuning), motor drives, and switching regulators. Unlike resistors which dissipate energy as heat, inductors store and release energy — making them fundamental to energy conversion circuits. This guide covers every core calculation for working with inductors.
Inductors behave opposite to capacitors in many ways. While capacitors block DC and pass AC, inductors pass DC and block high-frequency AC. Inductive reactance (XL) increases linearly with frequency, which is why inductors are used in low-pass filters and power supply smoothing. The RL time constant (τ = L/R) determines how quickly current builds up — important for switching power supplies, relay circuits, and motor controls.
Energy stored in an inductor's magnetic field follows the formula E = ½LI², which is analogous to a capacitor's E = ½CV². When current through an inductor is suddenly interrupted, this stored energy can produce dangerous voltage spikes (back-EMF) — which is why flyback diodes are essential in relay and motor driver circuits. Understanding these principles is key to safe and effective inductor circuit design.