André Marie Ampère (ăm´pēr; Fr. äNdrā´ märē´ äNpĕr´), 1775–1836, French physicist, mathematician, and natural philosopher. He was professor of mathematics at the École Polytechnique, Paris, and later at the Collège de France. Known for his contributions to electrodynamics, including the formulation of Ampère's law, he confirmed and amplified the work of Oersted on the relationship of electricity and magnetism, and he invented the astatic needle. The ampere was named for him. His writings include Recueil d'observations électro-dynamiques (1822) and Essai sur la philosophie des sciences (2 vol., 1834–43, vol. 1 repr. 1838).

See his Correspondance pub. by L. de Launay (3 vol., 1936–43).

Ampère, André Marie (1775–1836) French physicist and mathematician. He founded electrodynamics (now called electromagnetism) and performed numerous experiments to investigate the magnetic effects of electric currents. He devised techniques for detecting and measuring currents, and constructed an early type of galvanometer. Ampère's law (proposed by him) is a mathematical description of the magnetic force between two electric currents. His name is also commemorated in the fundamental unit of current, the ampere (A).