Measuring direction of DC ma with 2 digital multimeters

Discussion in 'General Electronics Chat' started by Jan Luthe, Oct 14, 2015.

  1. Jan Luthe

    Thread Starter Member

    Jan 10, 2015
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    Can Can I hook up 2 DMM in parallel with positive of DMM1 to negative of DMM2 and neg of DMM1 to +ve of DMM2 and install this in series with circuit in order to measure ma and which way the current is flowing?
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
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    one would be enough, most dmm's are auto ranging and auto polarity.current can only flow one direction at a time.
     
  3. Jan Luthe

    Thread Starter Member

    Jan 10, 2015
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    I think there are times when, in my circuit, the current reverses and I am trying to monitor when this happens. Basically in one direction the current is supplied by a 'charging system' and other times by a solar panel. I would like to determine when and by how much (ma).
     
  4. recklessrog

    Member

    May 23, 2013
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    102
    Strange how this thread should come up today, Having just repaired a piece of equipment, I was setting the o/p offset of an op amp circuit today, and although I own several DMM's, I have an analogue meter that has a center zero function (center = 0v, -ve left needle deflection, +ve right needle deflection) and I just prefer the visual effect of a swinging needle to the dancing reading of a DMM. (probably a sign of my age)
     
  5. recklessrog

    Member

    May 23, 2013
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    102

    That isn't current reversal, it's just the same direction current supplied from two different sources. Reversal would be whether for instance an accumulator is supplying current (discharged) or being charged. Current out/current in. As stated above, most Dmm's automatically show polarity, or a center zero analogue ammeter as used in vehicles would do the job.
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,003
    3,232
    A standard multimeter will measure both current directions, with a minus "-" sign at the left of the display showing minus to plus flow and no sign (blank) indicating plus to minus flow.

    Two multimeters are not needed (and would not indicate correctly if you did use two).
     
  7. Jan Luthe

    Thread Starter Member

    Jan 10, 2015
    51
    0
    Thanks crutschow. My question is asnwered.
     
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