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Measuring high voltage

  1. Apr 12, 2010 #1
    I am looking for a way to measure the voltage on a Kelvin Water Dropper that I've built. This is quite problematic since the charge is small and the voltage is high. The only way to do it, as it seems to me, is to measure by influence. Any suggestions?
  2. jcsd
  3. Apr 13, 2010 #2
    You could also use the field. Some suggestions:
    - build a simple Electroscope with an arm that moves up if the device is charged (some have a scale)
    - buy an electro field meter
    - attach your buckets to a plate capacitor and rotate a coil inside
    - measure the force between two capacitor plates
    - do something with a cathode ray tube
  4. Apr 13, 2010 #3
    Build a generating voltmeter. This is a rotating "fan" that alternately covers and uncovers capacitor plates. Feed the plates behind the rotating part to a high impedance scope or other High Z AC meter. AC signal will be proportional to the high voltage without contact. These are commonly used to sense the voltage on Van de Graff generators.
  5. Apr 15, 2010 #4
    Ok, thanks for your help!
  6. Apr 15, 2010 #5


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    Gold Member

    How can this work if Van De Graff generators produce DC power?
  7. Apr 15, 2010 #6


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    Science Advisor

    The rotating "fan" alternately shields and exposes the voltage on the target, producing an AC signal via capacitive coupling.
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