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High voltage Ac generation to apply to a capacitor

  1. Jul 5, 2010 #1
    Hi this is my first post on here

    I am looking to create a large voltage across a primarily capacitive load at around 190 kHz. At the moment i have a 175 Watt power amplifier which puts out 55 Vp.

    The output impedance also needs to be quite low < 100 ohms

    Does anyone have any idea how to do this. Im thinking maybe some sort of resonant circuit. Or maybe I will have to make a valve amplifier. The voltage should be at least 1 kV

    Any RF engineers out there? help would be very much appreciated

    thanks
    mark
     
  2. jcsd
  3. Jul 5, 2010 #2

    Averagesupernova

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    Whats wrong with a stepup transformer?
     
  4. Jul 6, 2010 #3
    It transforms the impedance up by a square of the turns ratio so say I wanted 500V, ratio 1:10 wouldn't it transform the impedance up by a facto of 100
     
  5. Jul 7, 2010 #4

    sophiecentaur

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    Why not Resonate the Capacitor with a suitable Inductor in series? You could get many times (XQ) the input voltage that way and an inductor is easy to make / buy. You need a Q of around 20, it would seem.
     
  6. Jul 7, 2010 #5

    berkeman

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    What's the application?
     
  7. Jul 8, 2010 #6
    sophiecentaur

    Yes I have thought of this idea. which seems pretty good to me but is quite difficult to achieve high Q.

    I was thinking if you put a secondary winding as in a transformer , would this step up the allready increased voltage that is created across the inductor?
    Also what is the voltage current phase relationship in a series resonant circuit. inphase?

    Berkemen

    Application is electric fields across wine which were doing a bit more of,
    http://www.stuff.co.nz/waikato-times/business/3190621/Better-wine-in-a-flash

    Id actually prefer the voltage to be in the order of 10 kV but this may be slightly harder to achieve.
     
  8. Jul 8, 2010 #7

    berkeman

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  9. Jul 8, 2010 #8
    It definitely tastes different the hard part is getting the frequency and E field correct to make it taste better. We have found a reasonably good combination that i can't really disclose
    This was confirmed on national tv by a wine critic

    But I need ideas to get a wacking great AC voltage for further development
     
  10. Jul 8, 2010 #9

    berkeman

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    Hopefully you and your advisors know a bit about high voltage safety, and about how to avoid creating RFI (radio frequency interference).

    Keep in mind also that if you can put that voltage across a smaller gap, then it takes a lot less voltage to make the same E field. So can you make a bunch of panels or something inside the wine container that are spaced closer together, and use a more standard voltage...?
     
  11. Jul 8, 2010 #10

    dlgoff

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    When I saw this:
    I about spit on my monitor. It does sound like a neat project.

    BTW I'll volunteer to be a taster. :biggrin:
     
  12. Jul 12, 2010 #11
    Berkemen its across a 4mm gap and the breakdown voltage of these is 25 kV/cm so we want to have control of the voltage up to this point ~14kV



    dlgoff Jonathan has actually finished with the project now unfortunately, otherwise I wouldn't be on here trying to conjure up some ideas.
     
  13. Jul 12, 2010 #12

    dlgoff

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    I was sort of joking with berkeman since we have a member here with the same "name". :smile:

    This schematic for a http://www.repairfaq.org/sam/hvgen32.pdf" [Broken] uses a couple of 555 timers and a television flyback transformer.
    Source: http://www.repairfaq.org/sam/samschem.htm#schahg"
     
    Last edited by a moderator: May 4, 2017
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