 Hans Christian Ørsted

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]

A physicist associated with Ørsted's experiment.

Hans Christian Ørsted (1777-1851) was a Danish physicist and chemist, best known for his discovery of electromagnetism. In 1820, Ørsted discovered that an electric current flowing through a wire could deflect a nearby compass needle, demonstrating the relationship between electrical current and magnetic fields. This pivotal discovery laid the groundwork for the field of electromagnetism and influenced later scientists, including André-Marie Ampère and James Clerk Maxwell.