Michael Faraday’s 1831 electromagnetic-induction experiment showed that changing magnetism can produce an electric current in a wire coil.
Faraday wound wire coils around an iron ring and connected one coil to a battery and the other to a galvanometer. The galvanometer moved only when the battery circuit was switched on or off, showing that a changing magnetic field induced a current in the neighboring coil. A steady magnetic field produced no continuing deflection.
Faraday extended the idea by moving magnets through coils and observing induced currents. These findings established electromagnetic induction, the principle behind electric generators, transformers, and many modern electrical devices.
The key condition is change: simply placing a motionless magnet beside a stationary coil does not continuously generate current. The direction of the induced current opposes the change that produced it, a relationship later expressed by Lenz’s law.