Is there anyone genius who could help me in fast switching negative high voltage?

Discussion in 'General Electronics Chat' started by chrisakuragi, Mar 3, 2011.

  1. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    What electronic component should i use if i have 1v signal to switch negative high voltage (-200V) very fast (1Mhz). Please help me...
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    There will have to be more than just one component involved. Traditional methods have used vacuum tubes, for instance.

    What is the application? What amount of current is involved?
     
  3. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    I wonder what the practical use would be?
     
  4. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    Thanks! we just need it in the laboratory.
    We want to switch on & off the (-200V, 0.01A supply) 1MHz per second or 1 million times per second.

    we have a 1 volt signal dc pulse, rectified from from square wave.

    What is the best electronic component for this application?
    we're planning to use transistor as a switch..
     
  5. mjhilger

    Member

    Feb 28, 2011
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    Are you looking for a schematic with the component(s) selected? Do you need to switch from the ground end or the -200v end? Do you care about the rise and fall time of the signal? Is the load purely resistive or reactive? I would use a MOSFET to switch, but the choice of exactly which one depends on your answers to the above questions. 1 volt would not switch the gate directly, as already stated, you will need additional amplification to raise the 1 volt pulse to at least 5 volts, and would like it in the 10 - 12 volt range. But depending on whether you are switching on the ground side or the -200 v side, you might have to shift the amplified drive signal down to switch between -190 v and -200 or so. Easily done with another transistor or so, but again how depends on exactly what you are trying to switch.
     
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  6. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    Sir, I really appreciate your answer! :D

    Sir, we need to switch from the -200v supply. actually we want the rise as "on" and the fall is "off". actually we dont have load sir because it is floating, the negative potential will actually be used as negative electric field to repel the negative ions inside our machine. The -200v is actually coming from the high-voltage device with very low current. Sir, it would be very helpful if you send the schematic and the actual specifications of the components! Thank you very much sir! God bless you! :)
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Actually, you need to give switching times, or slew rates. A 1Mhz 200V P-P sine wave would meet the requirements you've give so far. You are hinting at digital signals, but without the digital specs.

    There are a lot of ways to do this, the more important consideration is probably how the printed circuit board is laid out, since parasitics are going to be the big problem.

    What kind of load, for example? This is critical no matter if it is digital or analog. Load is expressed in ohm's in this case.

    You are not going to get any kind of meaningful answers unless you give meaningful information as to what the requirements are.

    One last comment, you have not mentioned what country this is being done in. 1 Mhz is in the middle of a commercial band of signals, pretty much international as far as I know. If you broadcast and jam these signals (200V is a lot of potential power) you are going to have the authorities down on your necks. I've seen a lot of people (especially from India) poh poh this, but it is an international requirement.
     
  8. russ_hensel

    Well-Known Member

    Jan 11, 2009
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    Might be easy to have this act as a fairly high power, broad band ( lots of harmonics ) rf transmitter. Probably not what you want.
     
  9. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    Sorry, but it doesn't make sense... Anyway, Thanks for the effort.
     
  10. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    Doesn't make sense? Or not what you wanted to hear?

    Two different things they are.
     
  11. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    Thank you very much sir! This really makes a lot of sense! :)
     
  12. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    It's not for you sir...
     
  13. t06afre

    AAC Fanatic!

    May 11, 2009
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    It seems like you think this is quite simple. And it is just for us whip something up. Electronics of this kind is not easy. If you want any help from us you have to put in some effort by your self. As a start go back to list posted by Bill M. And at least try to give some answers to the question he is asking D'oh!.
     
  14. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    Sorry sir.. thank you for that information. Please be patient with me because
    i thought this is quite simple for those of you who have expertise in this field.
    In regard to Mr. Bill's reply, i really don't figure out his point, that's why i commented that message, because i thought he was just mocking me.

    Anyway, sorry if i hurt you...
     
  15. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    Why are you building it? What would it be used for?
     
  16. chrisakuragi

    Thread Starter New Member

    Mar 3, 2011
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    We will use it as a gate for negative ions inside the chamber of ion beam.
     
  17. Wendy

    Moderator

    Mar 24, 2008
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    I suspect you have no technical background, and are using a translator program. The questions I asked were straightforward technical questions, the kind you have to answer (either to a designer or to yourself if you are the designer) before you can start drawing.

    Switching speed - how fast a signal goes from high to low or low to high in nanoseconds. Extremely fundamental question, basic digital electronics.

    Load - All oscillators and transmitters (not necessarily the same thing) are designed to feed a load, measured in ohms. Very fundamental electronics, also required for even the simplest design.

    You want information, you have to provide the specifications. This has not happened. You don't even understand the technical jargon requesting the specifications. This bodes ill for your project.

    We are a friendly group, but there are no magicians amongst us. Like I said earlier, there are lots of ways to do this electronically, but to build a black box with the unknowns isn't practical.

    The frequencies and switching speeds you have implied (but not specified) suggest a coax cable will be required. Coax cable also has an impedance (AKA, load). Again, basic electronics.
     
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