low current measurement of pico amps

Discussion in 'General Electronics Chat' started by nvssaravanan, Feb 3, 2011.

  1. nvssaravanan

    Thread Starter New Member

    Oct 4, 2010
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    HI all,

    I want to measure insulation resistance in the range of pico amps.
    i want to convert it to micro amps for mega ohmmeter indication.
    the test voltage for the measurement is about 27V DC.
    The mega ohmmeter working current is about 0 - 200mA.

    Which IC i have to use for amplifying the current for the above measurement.
     
  2. Adjuster

    Well-Known Member

    Dec 26, 2010
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    300
    Have you made a mistake with that meter current? A 1MΩ resistance measured with 200mA test current would dissipate 40W.

    To pass 200mA into 1MΩ, the test voltage would need to be 200kV!

    Perhaps you have a meter which also measures much lower resistances, with a higher test current?
     
    Last edited: Feb 3, 2011
  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,669
    804
    More like 40kW :eek:
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Quite so - my mistake.
     
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