How this calculator works
Current builds a magnetic field around an inductor. The energy relation applies when inductance is constant over the current range. Core saturation and hysteresis require a more complete magnetic model. Stored energy can cause a large terminal voltage when current is interrupted.
Formula
E = L I²/2; L = 2E/I²; |I| = sqrt(2E/L).
Worked example
An ideal 2 H inductor carrying 3 A stores 9 J. Storing 16 J in 2 H requires a current magnitude of 4 A.
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Frequently asked questions
Does current direction affect energy?
No. Current is squared, so this calculator uses its magnitude.
What if the core saturates?
Inductance then varies with current. Use the measured flux-linkage curve and integrate rather than assuming one fixed L.
Does resistance appear here?
Winding resistance dissipates power while current flows. It does not appear in the ideal magnetic stored-energy equation.