Nikola Tesla Books
84 84 HIGH FREQUENCY APPARATUS Use five inside turns as primary Use remaining ten turns as secondary Coil for D'Arsonval currents is composed of a spiral winding of copper ribbon in 15 turns Fig. 9.-Coil for the production of D'Arsonval currents simply constructed by winding up 15 turns of ½ in. copper ribbon is a flat spiral with a strip of the corrugated paper between to insulate one turn from the other. The kicking coil current is sent through the inside turns, say up to four or five, and the D'Arsonval current for the couch is taken from the remaining turns. The diagram, Fig. 9, makes this perfectly clear. The coil may be sealed up in a flat wooden case with taps brought from the respective turns of copper ribbon to binding posts on the outside of the case.
