reluctance

In a magnetic circuit, the magnetic resistance (Rm), also called reluctance, occurs. The magnetic resistance acts against the magnetic flux in the magnetic circuit at a constant magnetic flux.

Magnetic resistance is given by the ratio of the length (l) to the area (A) of the conductor and the permeability, its unit is 1/Henry. In comparison with ohmic resistance, which is given by the ratio of voltage (U) to current (I), magnetic resistance (Rm) is the ratio of magnetic voltage (Um) to magnetic flux (Phi).