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Re: Flat coils & undamped waves (was Wire Length)

Original poster: "Gary Peterson" <g.peterson@xxxxxxxxxxxx>

"The one fatal defect most frequently present in oscillatory systems is a large internal capacity." -- Nikola Tesla, ca. 1916"

Original poster: "David Thomson" <dwt@xxxxxxxxxxxx>

. . . bifilar wound coils . . . make
great electromagnets. . . .

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

   Read some of his earlier patents.  Guess he learned something!



Thank you for bringing the list's attention to Tesla's COIL FOR ELECTROMAGNETS, July 7, 1893, U.S. Patent No. 512,430, Jan. 9, 1894. Let me begin by pointing out Tesla's stated purpose for the bifilar coil winding.

"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."

This means that Tesla intended to use bifilar-wound inductors in applications where an inductor and a capacitor would be connected together in order to form a "tuned circuit." It is true that the helical resonator and the elevated terminal of a Tesla coil RF transmitter form the substantial part of a tuned circuit. Nevertheless, deliberate augmentation of the resonator's internal capacity as a substitute for what might be called the 'external capacity' formed by the elevated terminal and its distant counterparts would be self defeating. To assert that this was Tesla's true intention is quite ridiculous.

Gary Peterson

Re: Undamped oscillations

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

   Quote from Tesla patent 512,430 Jan. 9, 1894:

. . . "I have found that in every coil there exists a certain relation between its self-induction and capacity that permits a current of given frequency and potential to pass through it with no other opposition than that of ohmic resistance. . . .

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. Bottom line is that in 1894 Tesla apparently thought self-capacitance was enough of a virtue to patent it. By 1916 he had obviously learned otherwise.