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Resonant frequency material

  1. Oct 8, 2012 #1
    Hi , I've been wondering is there a metal or some kind of material that can hold a magnetic flux like a transformer core iron and alloys usually do, but at certain frequencies have a resonant effect, like putting a let's say 100hz frequency in the primary winding could make the electromagnetic field much stronger than at other frequencies?
     
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  3. Oct 8, 2012 #2

    berkeman

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    Wind a secondary winding and add a capacitor to give you the resonance you want...
     
  4. Oct 8, 2012 #3
    i see your point Russ, but my idea was about the transformer core material efficiency itself.
    That's why I raised such a question that we all know there are losses in heat and other losses in the copper wire and the iron core I just thought that which has a certain resonant frequency at which it makes the flux stronger, or is it not real or possible?
     
  5. Oct 8, 2012 #4

    berkeman

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    (I'm often mistaken for the other Engineering Mentor Russ -- we look a lot alike) :smile:

    I don't think you can do much with the material itself (iron for low frequencies, ferrite for high frequencies). The best you can do is make it low-loss so that the external circuitry can form a resonant circuit.

    There might be something I'm missing, so we'll see if others can chime in with suggestions...
     
  6. Oct 9, 2012 #5
    Oh damn:) I really saw that your name was Russ but only now I realize that your not:D
    Sorry for my mistake.
    Maybe there is some quantum entanglement between you and him .. :D

    Well I had this idea when thinking about Nikola Tesla , well no doubt Tesla was a genius man but he also was very mystical especially his personality and many crakpots use some of his ideas and change them to suit their needs but my point was that Tesla made a claim tad if you reach a systems resonant frequency then at that frequency the system vibrates so much more than at others , like a truss bridge , I think we have one example of the tacoma narrows bridge.
    So I just thought that maybe a transformer core could make something similar in electromagnetic field, at a certain frequency just multiply the flux strength.
    Or any other like a gas being heated by electromagnetic induction ,but that should mean that the subatomic particles of the gas in the material should have these resonant properties , but i'm not sure that subatomic particles have such properties like a resonance at certain frequencies.
     
  7. Oct 9, 2012 #6
    Are you suggesting that Tesla "discovered" the resonance? This is a well know phenomenon and it was not discovered (or claimed?) by Tesla.
    Tesla made use of resonance in his Tesla coil. Maybe here is the source of confusion.
     
  8. Oct 9, 2012 #7
    No by no means i wanted to assert that Tesla invented that and actually like you said there is not much to invent there it just is, but my original question or at least the that I elaborated a little bit in my last post remains active.

    Are there resonant properties of elementary particles like photons of the electromagnetic field and could there be a possible material that would resonate at let's say 100hz much more than at other frequencies making the magnetic flux much stronger at that frequency?


    Thanks.
     
  9. Oct 9, 2012 #8

    berkeman

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    Please keep in mind that even if there were some sort of resonance, you wouldn't get more flux than the energy you are putting in. That's how resonances work -- they store the energy that you've put in efficiently (with little damping).
     
  10. Oct 9, 2012 #9
    Yes I remembered that too just now that no way could make it more than 100% effective otherwise we would have a free energy perpetual motion (glory to all the youtubers) device:D
    And that is not possible.
     
  11. Oct 9, 2012 #10

    sophiecentaur

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    I would suspect that a resonance in a material would probably increase the losses at that frequency rather than reduce them. Would it not correspond to absorption?
     
  12. Oct 10, 2012 #11
    From transformer iron you will get no resonance at all, from ferrite neither.

    But from YIG yes. It's a bit different from a ferromagnetic alloy, though. It uses spin flipping. Its resonance frequency is precisely proportional to the externally applied magnetic field, and this over a very wide range in the GHz.

    YIG is used to define the frequency of oscillators. By changing the current in a coil, you get a frequency directly proportional, over several octaves. It is used in non-FFT spectrum analyzers - meanwhile we have Direct Digital Synthesis but its spectrum purity is bad, I suppose it hasn't and won't replace YIG in spectrum analyzers. FFT is more fashionable but has its limits.

    A typical non-FFT spectrum analyzer has a DAC with a huge resolution to create the current that defines the YIG frequency. In a first phase, or from time to time, the analyzer creates a few currents and measures the obtained oscillator frequency, then it computes the linearizing correction. After that, it can inject (after the correction is computed) the necessary current for any frequency, and make linear or logarithmic frequency sweeps.

    http://en.wikipedia.org/wiki/Yttrium_iron_garnet
    http://en.wikipedia.org/wiki/YIG_filter
    http://en.wikipedia.org/wiki/Spectrum_analyzer
     
  13. Oct 11, 2012 #12
    May be you need a couple of antennas rather than a transformer.
     
  14. Oct 11, 2012 #13

    sophiecentaur

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    That would not be what the OP wants to do. The question was about properties of materials and not producing resonance by choice of 'geometry' of a circuit. YIG would be a suitable example of this (as suggested earlier).
     
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