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High Voltage Regulator Circuit Help

Discussion in 'General Electronics Discussion' started by NantachieRat, Aug 11, 2013.

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  1. NantachieRat

    NantachieRat

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    Aug 4, 2013
    I am working on a power supply for vacuum tube circuits. It is a full wave voltage doubler with an input of 120 Vrms fron the transformer secondary. It gives a B+ of 330 Vdc. I need a regulator circuit to be able to get a B+ of 125 to 250 volts. I have several high voltage transistors and I was wondering if anyone knows of a configuration that would work.
     

    Attached Files:

    Last edited: Aug 11, 2013
  2. GonzoEngineer

    GonzoEngineer

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    Dec 2, 2011
    What you need is called a Buck Regulator, and is easily implemented with a series switch, inductor and capacitor. You can control the series switch with a PWM chip.
     
  3. techiesteve

    techiesteve

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    Jul 27, 2013
    Do you intend your HT to be variable between 125V - 250V, and what current do you need to supply?
     
  4. NantachieRat

    NantachieRat

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    Aug 4, 2013
    Do you mean use a transistor as a series switch and configure the coil and cap as a choke input filter?
     
  5. NantachieRat

    NantachieRat

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    Aug 4, 2013
    about 500 MA.
     
  6. GonzoEngineer

    GonzoEngineer

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    Dec 2, 2011
    A google of "Buck Regulator" will provide a wealth of circuits.
     
    Last edited: Aug 12, 2013
  7. duke37

    duke37

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    Jan 9, 2011
    500MA. You don't do things by half !

    Give us a specfication of your requirement including realistic current, voltages (fixed or variable) and ripple.

    What will the power supply be used for, a large amplifier should be able to manage 330V?
     
  8. BobK

    BobK

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    1,688
    Jan 5, 2010
    500MA at 250V is 125 Gigawatts (pronounced Jigawatts)!

    Doc Brown
     
  9. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    NantachieRat, Duke and BobK are pulling your leg. I think they know that you mean 500 milliamps, but you wrote 500 MA, which is 500 mega-amps. 500 milliamps should be written 500 mA. The difference is important; we are engineers here.
     
  10. NantachieRat

    NantachieRat

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    Aug 4, 2013
    They don't bother me! I am down to 145 MA wide open, this is the point where voltage begins to fall off rapidly with any increase in current. I am looking at a working load of 60 to 70 MA. I have a schematic I'd like you to look at, it is a vacuum tube type regulator for high voltage tube circuits. I have several hundred tubes on hand, and I have some tube experiments, so I am going to try to build an all tube voltage regulator. Please excuse the typo! I did mean mA. I consider myself an engineer too!
     

    Attached Files:

    Last edited: Aug 16, 2013
  11. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    That should be 145mA. Mind the case sensitivity and follow Kris' advice.

    MA <>mA

    That is important.

    Here are some regulator designs specifically for tube circuits.
     
    Last edited: Aug 16, 2013
  12. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    In that case, why are you repeating your error? Because writing mega-amps when you mean milliamps is not a cool way to advertise your uniqueness; it's a way to be wrong and embarrass yourself.
     
  13. duke37

    duke37

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    771
    Jan 9, 2011
    The tube circuit you show looks good. There could be problems with stability as with any feedback amplifier. Do not exceed the power rating of the 6080.

    Great care is necessary in using correct units. Sloppy use has caused several disasters.
     
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