10X Probe Breakdown Voltage

Discussion in 'General Electronics Chat' started by navon, Sep 22, 2013.

  1. navon

    Thread Starter New Member

    Mar 4, 2010
    1
    0
    What define the scope probe max voltage limit? Is it mainly the compensation cap inside the probe?
    As far as I understand the probes at worst only have about 250V compensation caps.
    When measuring e.g. tube amp I understand that in DC coupling position all the voltage coming is across the probe. Is it then that in AC coupling only the scope's coupling cap define the voltage limit?

    http://imageshack.us/a/img6/7364/0wm9.jpg

    If the case is like that,then it doesn't differ to the scope if You use 1X or 10X probe in AC coupling,always the scope's AC coupling cap gets full DC voltage across it?

    Then using 600V 10X probe instead of 400V 10X probe doesn't give any more protection to your scope?

    Solution to this is of course to use 1000V cap attached to the tip of a probe and to discharge it to the ground before the next measurement.
    How then does it affect the position of scope's coupling switch? Should I use AC or DC coupling? Is only difference how the scope's coupling cap discharge through 9MΩ resistor and leaving possible some charge on it?

    What about building resistor voltage divider before the scope probe or should I use it alone without the probe?


    Any help appreciated :)
     
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