Faraday's Law of Induction

Making voltage from changing magnetism.

If the magnetic flux through a loop of wire changes, an EMF is induced in the loop. Flux depends on field strength, loop area and the angle between them, so moving a magnet, changing the area or turning the loop can each create a voltage.

The induced EMF is proportional to how fast the flux changes and to the number of turns. This principle drives generators, induction cooktops, microphones and wireless chargers.

• Steady flux gives no EMF; only change does.
• More turns give a larger EMF.
• Faster change gives a larger EMF.

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