School of Physics Lecture Demonstration Manual

Eb-4 Eddy Currents

Published: Tuesday 14 March 2006 - Updated: Tuesday 29 March 2011


To demonstrate that when a solid conductor is threaded by a changing magnetic field circulating currents (eddy currents) are induced in the conductor.



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Eddy Currents Pic


Eddy Currents


The apparatus consists of Aluminium plate pendula which may be set swinging between the poles of a permanent magnet.

The demonstration shows that when the solid vane pendulum swings between the poles of the magnet, the induced currents (Eddy currents) damps the motion dramatically. Replacing the solid vane with one having cuts taken out of it, allows comparison of the damping effect and a determination of the direction of the circulating loops of current.

Safety notes

Electrical safety 


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