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Self-resonating coils

  1. May 16, 2006 #1
    Hello,

    I am teaching myself about oscillator circuits and I was wondering if someone could help me understand if it is possible to make a coil that will resonate at a natural frequency. I was reading some articles about experiments Nicola Tesla performed and the document I read (don't remember where I read it from) mentioned that Tesla made oscillators that resonated at some harmonics of the earth's natural resonant frequency. I read about the Schumann resonance (7.8Hz) but realized that it would be hardly practical to make a coil the size of Texas to resonate at that frequency. But is it possible to work off of a harmonic of this. Does anyone know about this at all?

    Thank you,
    Jason O
     
  2. jcsd
  3. May 16, 2006 #2

    berkeman

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    Staff: Mentor

    Coil resonance is due to the interplay of the inductance of the coil and any parasitic or explicit capacitance. Energy can resonate back and forth between being stored on the capacitance and stored in the current in the inductance. For a low-loss LC resonant circuit, the cap voltage is maximum when the coil current is zero, and the cap voltage is zero when the coil current is at maximum.

    I don't know anything about Schumann resonance or the earth's "natural resonant frequency". That part sounds fishy to me....
     
  4. May 17, 2006 #3
    This is probably not the greatest reference for earth resonance but there is a blurb written about it here: http://en.wikipedia.org/wiki/Schumann_resonance

    Here's another source talking about the same thing too: http://www.oulu.fi/~spaceweb/textbook/schumann.html

    And here's a link to a university that has taken some measurments on it:
    http://147.175.143.11/

    Since it has been proven that these natural frequencies exist, I was wondering how you could make a coil that would resonate with them. I'm not concerned about how strong or weak the effect is but I want to understand how to do it using the coils own capacitance rather than making a tuned tank circuit.
     
    Last edited: May 17, 2006
  5. Sep 12, 2010 #4
    tesla did it, he made a self resonating circuit with a coil the size of texas while he was in colorado springs, he also made his own caps with a rather enormous size making the low frequencies that he tested for schuman cavity trtansmission possible. I believe that he had a self tuning mechanism for impedance matching, similar to military grade hf circuit couplers as the impedance of the earths electromagnetic field is always changing. While I understand that this feat is simply not feasable for you you should try to make several coils and circuits that resonate with one another for increased inductive efficiency. make one wind of one circuit with one wind of another. Then place the coils wound in this fashion within close proximity of one another and have the circuits within a little off of one another ex. if you have four coils and four circuits, then they will be within 1/8 out from each other so that the collapsing coil charges the coil that is wound with it. Essentially a self regenerating self resonating circuit. This would require tri phase power and a little imagination along with a voltage doubling circuit or possibly "even more efficiently a voltage quadroupler circuit" would ensure very high voltage with low current at whatever frequency that you desire by controlling the imedance of the two side-by side coils. or even more as desired.
     
  6. Sep 12, 2010 #5
    P.S. links no. 2 and 3 are broken, given the age of this post it would be logical to assume that the pages have been taken down. Too bad though I would have loved to have read them.
     
  7. Sep 13, 2010 #6
    Really the size of texas?...
     
  8. Sep 13, 2010 #7
    the bigger the better....... LOL
     
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