Stored Energy in Magnetically Coupled Inductors Integration over multidimensional current space

Mutual Flux Weakly Coupled Circuits

Two Coupled Inductors

General Integration Path Conservative magnetic field Energy independent of path of integration

Simple Path of Integration

Other Simple Path of Integration

Equivalence In a conservative field, Lkm = Lmk In general:

Aiding and Opposing Flux When both currents enter the polarity marks or when both currents exit from the polarity marks, the mutual inductance, Lkm is considered as positive. Otherwise, Lkm is negative.

Aiding and Opposing Flux Here, L12 = L21 would be considered negative.