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Incoming links: Compass
Hans Christian Ørsted Created 2026-10-31 Updated 2026-11-05
Hans Christian Ørsted showed that an electric current can deflect a nearby compass needle. His 1820 announcement emphasized that the electric circuit had to be complete in these experiments and described repeating the observations with a more powerful battery. The compass needle supplied a mechanical readout connecting the electric current with magnetism. The wire's arrangement relative to the compass made this a direct experiment on the magnetic field associated with an electric current.[ref]
Experiments on the Effect of a Current of Electricity on the Magnetic Needle by Hans Christian Ørsted. 1820 announcement, opening experiments and complete-circuit requirement
Portrait of Hans Christian Ørsted
. Portrait by Christian Albrecht Jensen, 1842; public-domain reproduction hosted by Wikimedia Commons. Source.