Voltage Multiplier - DVM Can't Read Voltage

Discussion in 'The Projects Forum' started by ngmallaboutcircuits, Jan 30, 2010.

  1. ngmallaboutcircuits

    Thread Starter New Member

    Jan 30, 2010
    1
    0
    I have a voltage multiplier circuit (basically a villard cascade design) using several stages of diodes and caps. My output should be in the 500V - 600V range (DC of course) and I believe is working as it is powering the sensor I am using it for.

    With that said, I am having no luck measuring it with my 10MOhm input resistance DVM. I suspect such a circuit is easily loaded down, but I'd think 10MOhms would be enough to prevent such a thing. I'd also have to assume that the DVM manufacturer probably made the input resistance as high as possible without limiting the current below that which their A to D could handle.

    So what does one do in such a situation?
     
  2. 3ldon

    Active Member

    Jan 9, 2010
    82
    3
    Determine that the dmm works in the first place.
    10Mohm load would load down a 20Kv multiplier significantly, not a 500 volt system.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    What is the base oscillator? The drive must be low impedance (very). A square wave also works best.

    A schematic would let folks help better.
     
  4. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    Increase the input resistance of the DVM.

    Place as much as twenty 10MΩ or 22MΩ resistor in series with the DVM. Measure and record the unknown voltage reading, using a suitable range.

    Using the same arrangement and DVM voltage range to measure a known DC voltage, preferably one that is more than 50% of the unknown voltage and work out the actual voltage from the readings.
     
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