Enter your Inductance (L) in henries and Current (I) in amperes, and this Inductor Energy Calculator works out the stored energy in your inductor using the formula E = ½LI² — giving you the result in joules.
Stored Energy
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The energy stored in an inductor is calculated using the formula E = ½LI², where E is the energy in joules, L is the inductance in henries, and I is the current in amperes.
Inductors store energy in the form of a magnetic field created around the coil when current flows through it. The energy is proportional to the square of the current and the inductance value.
Common inductance values range from microhenries (μH) to millihenries (mH). Small inductors might have values around 1-100 μH, while larger power inductors can have values of several mH.
The energy is proportional to I² because the magnetic field strength increases linearly with current, but the energy stored in the magnetic field is proportional to the square of the field strength.
Inductors are used in power supplies, switching circuits, filters, and energy storage systems. They're commonly found in DC-DC converters, motor drives, and surge protection circuits.
Higher inductance values allow for greater energy storage at the same current level. Doubling the inductance doubles the stored energy, while doubling the current quadruples the stored energy.
When current through an inductor is suddenly stopped, the stored magnetic energy is released, often creating a voltage spike. This is why flyback diodes are used in switching circuits.
Theoretical calculations are very accurate for ideal inductors. Real-world factors like core losses, resistance, and temperature can slightly affect actual energy storage, but the formula provides excellent approximations.