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Eddy currents
Intermediate
Circulating currents induced in bulk conductors.
Changing flux induces circulating currents in bulk conductors, heating them and opposing motion. Laminated cores reduce them in transformers.
Induction cookers heat pans with eddy currents.
Useful or harmful depending on the application.
In more detail
Eddy currents are loops of induced current in a conductor that changes in flux, dissipating energy as heat. They oppose the motion or change that causes them.
Real-world uses
- Induction hobs heat metal pans with eddy currents.
- Metal detectors use eddy currents to find metal objects.
- Metal detectors and induction hobs work by inducing eddy currents in conductors.
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Frequently asked questions
Why are laminated cores used?
Thin laminations reduce eddy currents and hence energy losses in transformers.
Can eddy currents be useful?
Yes, for braking, heating and detection.
Why are eddy currents bad in transformers?
They waste energy as heat, so laminated cores are used to break them into thin paths.
Related topics in Magnetism & Induction
Faraday's law · Lenz's law · Motional emf · Eddy current braking · Self-inductance · Inductance of a solenoid