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Tesla's ether theories and longitudinal waves explained in "Wardenclyffe"

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  • #61
    I found a nice overview article on mosfet ringing:
    Last edited by kyle_dellaquila; 10-05-2020, 05:28 AM.


    • #62
      For those interested in the "ether density detector" (EDD) described on page 4 in this thread:
      Here are the KiCAD generated production files for the PCB. (see attached zip file) The PCB should be cut in 3 pieces:
      - the right side is for use as a ATMega328 programmer (1)
      - the left side is the EDD (2) with
      - below it a JTAG to ISP converter (3)
      Parts 1 and 3 are just added because I don't have those and they may come in handy at some point.
      The EDD is very basic, just a proof of concept kind of thing. Much more functionality can be added later if it produces interesting results. It is for use with a Nokia 5110 LCD display and a 9V battery.
      I also just completed a first draft of the program. It does compile clean but I have not ran any tests with it. But if you want to see its code, please refer to the attached file.

      Questions and suggestions are all welcome


      EDIT: I just found some errors in the EDD program, so don't use it as-is. Once I have fully debugged it I will post a working version. This one is a good example of what it takes....
      Attached Files
      Last edited by Ernst; 10-20-2020, 06:18 AM.


      • #63
        just glanced over this thread. Mosfet ringing most if the time is solved with a 10 ohm metal oxide resistor near the gate. It not only dampens the ringing, but also limits the charge / discharge current. and thus the switching speed.

        for higher discharge a ultra fast diode can be placed parallel over de resisitor (in reverse)

        this Gate driver IC: infineon 1EDI60I12AF
        ​has different paths for charging and discharging.

        so you can use 2 resistors: one for charge and one for discharge.
        it is also isolated, so you can use it for high side switching.

        Another Idea is using zeners but they also need to be very fast

        hope this helps,


        • #64
          The main characteristic that I looked at when choosing my components was speed. The 1EDI60I12AF gate driver has a typical delay of 300ns which is way too long for my design. Adding a resistor to the MOSFET gate slows the switching of the MOSFET which is also not what I want. I managed to get the ringing down to an acceptable level with some capacitors, UF diodes and a TVS. It now looks like this:

          It doesn't have to be perfect as it is a signal that goes to a vacuum tube grid. And whether the grid is +150V flat or with peaks to +300V the tube will conduct, likewise -150V flat or with peaks to -300V will just block any current.
          The circuit seems to be working quite reliably now, so I hope to be able to upload the KiCAD files and BOM soon.
          (very busy these days)

          Last edited by Ernst; 12-02-2020, 03:41 AM.


          • #65
            I've read most of Tesla's articles, I wanted to know if you read De Volson Woods' gaseous ether paper. Tesla refers to him in one of his articles and says it has rare academic rigour or something like that. The thing I found really interesting is that when Tesla quotes his density for the ether being about 800 billions times less than air (please correct me if I'm wrong) it seems that he got that value from De Volson Woods paper or confirmed it himself.

            Another scientist Tesla quotes in an article is Prof Bjerknes. His work was on the analogous nature of fluid vibration and the effects observed in electric and magnetic fields. That particular paper is quite eye opening actually and he and his son derived some analogous equations to maxwells.

            Anyway I thought that might help give even more perspective on Tesla's ideas at that time.

            Both papers are attached


            Attached Files


            • #66
              Yes, I have the the Volson Wood paper, but I didn't have that Bjerknes book. I will have a look.

              Just to complete the info:
              Tesla referring to de Volson Wood on April 8th, 1934 in the New York Times; "An Inventor's Seasoned Ideas":
              It is true," said Mr. Tesla, "that many scientific minds envisaged the theory of a gaseous ether, but it was rejected again and-again because in such a medium longitudinal waves would be propagated with infinite velocity. Lord Kelvin conceived the so-called contractile ether, possessing properties which would result in a finite velocity of longitudinal waves. In 1885, however, an academic dissertation was published by Prof. De Volson Wood, an American, at a Hoboken institution, which dealt with a gaseous ether in which the elasticity, density and specific heat were determined with rare academic elegance. But, so far, everything pertaining to the subject was purely theoretical.
              Tesla gives us two widely different values for the density, but it is not clear is he is talking about the ether or about "the medium".
              The first is in a quote from September 22nd , 1929:
              “On further investigation I found that this gas was so light that a volume equal to that of the earth would weigh only about one-twentieth of a pound.”
              This works out to be 2.093 x 10 -26 g/ml.
              The second is in this quote from October 13th, 1932:
              “Its density has been first estimated by Lord Kelvin and conformably to his finding a column of one square centimetre cross section and of a length such that light, traveling at a rate of three hundred thousands kilometres per second, would require one year to traverse it, should weigh 4.8 grams.”
              This works out to be 5.074 x 10 -18 g/ml.
              Dry air at 20 C has a density of 1.2041 x 10 -3 g/ml, 0ne 800 billionth of which would be 1.505 x 10 -15 g/ml. Roughly 330x denser than Tesla's highest value.
              De Volson Wood mentions 2x 10 -24 pound/ft³ which would be 3.204 x 10 -26 g/ml and is close to Tesla's first number.

              I have one article in which Tesla refers to prof Bjerknes, it is of Dec 21st, 1892: "On the Dissipation of Electrical Energy of the Hertz Resonator" published in the Electrical Engineer. It starts with this:
              Anyone who, like myself, has had the pleasure of witnessing the beautiful demonstrations with vibrating diaphragms which Prof. Bjerknes, exhibited in person at the Paris Exposition in 1880, must have admired his ability and painstaking care to such a degree, as to have an almost implicit faith in the correctness of observations made by him. His experiments "On the Dissipation of the Electrical Energy of the Hertz Resonator," which are described in the issue of Dec. 14, of THE ELECTRICAL ENGINEER, are prepared in the same ingenious and skillful manner, and the conclusions drawn from them are all the more interesting as they agree with the theories put forth by the most advanced thinkers. There can not be the slightest doubt as to the truth of these conclusions, yet the statements which follow may serve to explain in part the results arrived at in a different manner; and with this object in view I venture to call attention to a condition with which, in investigations such as those of Prof. Bjerknes, the experimenter is confronted.
              and ends with:
              Taking the above views, I believe, that in the experiments of Prof. Bjerknes which lead him to undoubtedly correct conclusions, the air is a factor fully as important, if not more so, than the resistance of the metals.
              I don't see a reference to the book that you linked... But thanks anyway!