Magneto-motive force

The magneto-motive force, often abbreviated as MMF is any physical driving force, such as a current in a coil, that produces magnetic flux.

The MMF is measured in Ampere-turns (e.g., current in a coil times number of turns), but its SI unit is Ampere [A]. The MMF is related to the magnetic field strength by Amperes law.

The MMF plays the same role in magnetic circuits that the electro-motive force (EMF) plays in electric circuits, which explains the choice of name.

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