Original poster: "Gary Peterson" <g.peterson@xxxxxxxxxxxx>Following up on some earlier posts about Tesla's COIL FOR ELECTROMAGNETS, an electrical oscillator for powering HF lighting tubes that includes a series-wound bifilar coil is shown in the book NIKOLA TESLA: LECTURE BEFORE THE NEW YORK ACADEMY OF SCIENCES - APRIL 6, 1897 (p. 37, Fig. 4). The caption reads, "Coil wound to secure greatly increased capacity." The circuit diagram and accompanying text is included as part of the book's description at www.tfcbooks.com/mall/more/351ntl.htm .
Original poster: "Gary Peterson" <g.peterson@xxxxxxxxxxxx> . . . COIL FOR ELECTROMAGNETS, July 7, 1893, U.S. Patent No. 512,430, Jan. 9, 1894. . . ."My present invention has for its object to avoid the employment of condensers which are expensive, cumbersome and difficult to maintain in perfect condition, and to so construct the coils themselves as to accomplish the same ultimate object."
Original poster: Ed Phillips <evp@xxxxxxxxxxx> . . . The patent drawing shows a bifilar spiral coil but I can't find any further statement about it or of any special properties attributed to it. . . .