Multimeter Ranges

Discussion in 'General Electronics Chat' started by sol, Nov 1, 2010.

  1. sol

    Thread Starter New Member

    Nov 1, 2010
    9
    0
    Hi all, I’m new to these forums so a simple question.

    My digital multimeter manual says when reading AC and DC current the ranges are from 40mA to 400mA on one setting, and from 4A to 10A on the other.

    So what about readings above 400mA and below 4A?

    I get a overload error on the mA setting for the circuit I am testing and the A reading doesn’t make sense to me.

    Thanks.
     
  2. Rbeckett

    Member

    Sep 3, 2010
    205
    32
    Build a current divider for testing your stuff above 400Ma. It will prevent damage to your DVOM if you overload it too often.
    Bob
     
  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,772
    931
    You can use the high range 4-10A setting to read currents less than 4A, but the lower the reading the less accurate it will be on that scale. The 4-10 spec probably means the meter is 'accurate' in that range on that scale. (whatever accurate means nowadays) :)
     
  4. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    Never seen a digital meter with such strange, discontinue current ranges.

    Can you show us a picture of the range dial of the meter, please.
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    What is the brand and model number?

    Would you happen to have a link to an identical meter online, at a sales site or similar?
     
  6. sol

    Thread Starter New Member

    Nov 1, 2010
    9
    0
    It’s a UNI-T, UT60A.
    Here’s is a link to site: http://www.uni-trend.com/UT60A.html#

    This was from manual:
    [​IMG][​IMG][​IMG]

    I am trying to test a circuit which i think is between 500mA to 1A.

    [​IMG][​IMG][​IMG]
     
    Last edited: Nov 4, 2010
  7. DonQ

    Active Member

    May 6, 2009
    320
    11
    Forget the Hz thing, you have 3 ranges, each of which has 2 internally selected auto-ranges

    uA goes 0 to 400uA, or 0 to 4000uA (same as 0 to 0.4mA, or 0 to 4 mA)
    mA goes 0 to 40mA, or 0 to 400mA
    A goes 0 to 4A (same as 4000mA), or 0 to 10A (you would think 40A, but there is probably a fuse)

    So your ranges all start at zero and go to

    Code ( (Unknown Language)):
    1.  
    2.     0.4 mA - uA range
    3.     4   mA - uA range
    4.    40   mA - mA range
    5.   400   mA - mA range
    6.  4000   mA -  A range
    7. 10000   mA -  A range


    It should be simple now.

    The only thing is, if you have already blown the current fuse, the 'A' range (at least) will not work correctly.
     
  8. sol

    Thread Starter New Member

    Nov 1, 2010
    9
    0
    Ok i understand now.

    The A reading i didn't get was 0.25 which would be 250 mA? (4A to 10A setting)
    But when i had it on 40mA to 400mA it was overloading which means it should be a lot higher than 250mA?
    I am right in that?
     
  9. DonQ

    Active Member

    May 6, 2009
    320
    11
    that would normally be right. Check your fuse, it might be blown, which would make the high current readings lie. If you accidentally try to measure a voltage while the meter is set up for current, you will blow it right away. (At least 9 out of 10 meters in the world have blown fuses, higher than that for people new to meters.)

    You usually have to open the case to get to it.
     
  10. sol

    Thread Starter New Member

    Nov 1, 2010
    9
    0
    Yes i checked the fuse and it was ok.
    So that means the reading must still be above 400 mA?
     
  11. DonQ

    Active Member

    May 6, 2009
    320
    11
    Hard to tell from here, but if it was over-range on the lower setting, assuming that the meter is working right, then it was above 400mA. Why it would then say 250 on the higher range is unknown.

    Sometimes, the meter itself can change the operation of the device it is hooked to. The 'amp meter' actually measures the voltage across a known resistor (usually a low value) that is inside the meter. This can mess up some circuits. Or the device you're measuring could just happen to change while you're measuring.

    Like I said, hard to tell from here. Just keep messing with it, you'll figure it out.
     
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