# Hopkinson's law (MMF)

## Description

where R is the electrical resistance of that material. Hopkinson’s law is a counterpart to Ohm’s law used in magnetic circuits. In electronic circuits, Ohm’s law is an empirical relation between the EMF applied across an element and the current I it generates through that element. Hopkinson’s law can be interpreted either as an empirical equation that works for some materials, or it may serve as a definition of reluctance.

Related formulas## Variables

MMF | The Magnetomotive Force (A*turns) |

Φ | The Magnetic Flux through the magnetic element (Wb) |

R_{m} | The Magnetic Reluctance of the element (A*turns/Wb) |