INDUCTION COIL • DICCIONARIO INGLES.COM • Definition of Induction coil

... telephone experimentation to the search for the wireless. He grounded his wires and sent high currents into the earth, but improved his system and took another step toward the final achievement by adding a large induction coil to his sending equipment. He suggested that the spoken word might be sent as well as dots and dashes, and so sought the wireless telephone as well as the wireless telegraph. Like his predecessors, his experiments were successful ...

— Masters of Space - Morse, Thompson, Bell, Marconi, Carty • Walter Kellogg Towers