Energy Stored in Inductor Calculator Formula

Understand the math behind the energy stored in inductor calculator. Each variable explained with a worked example.

Formulas Used

Stored Energy

energy = 0.5 * inductance * 1e-3 * pow(current, 2)

Stored Energy (mJ)

energy_mj = 0.5 * inductance * 1e-3 * pow(current, 2) * 1000

Variables

VariableDescriptionDefault
inductanceInductance(mH)100
currentCurrent(A)2

How It Works

Energy in an Inductor

An inductor stores energy in its magnetic field when current flows through it.

Formula

E = (1/2) * L * I²

This energy is released when the current decreases. The magnetic field collapses, driving current through the circuit.

Worked Example

A 100 mH inductor carrying 2 A.

inductance = 100current = 2
  1. 01E = 0.5 * L * I²
  2. 02E = 0.5 * 100e-3 * 4
  3. 03E = 0.5 * 0.4
  4. 04E = 0.2 J = 200 mJ

Frequently Asked Questions

Where is inductor energy storage used?

Inductors store energy in switch-mode power supplies, DC-DC converters, and energy harvesting circuits where energy is rapidly cycled.

What happens to the energy when current is interrupted?

The collapsing magnetic field generates a voltage spike to try to maintain current flow. This is the principle behind ignition coils and boost converters.

How does inductor energy compare to capacitor energy?

Capacitors store energy in an electric field (E=0.5CV²), inductors in a magnetic field (E=0.5LI²). Both are proportional to the square of the respective variable.