Wilhelm Eduard Weber
German physicist Wilhelm Eduard Weber made use of the bifilar coil in his 1848 electrodynamometer. Large examples were used in inventor Daniel McFarland Cook's 1871 "Electro-Magnetic Battery" and Nikola Tesla's high frequency power experiments at the end of the 1800s. Nikola Tesla patented the Bifilar Coil on January 9, 1894, referring to it as a “Coil for Electro Magnets”.