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Thread: Small current doesn't flow through multimeter set to 200 mA but does when set to 10 A

  1. #1

    Default Small current doesn't flow through multimeter set to 200 mA but does when set to 10 A

    I wanted to see how much current was going through a regular LED at a certain voltage. It should have been 20 or 30 mA. I set my multimeter to scale 200 mA and wire up appropriately and the LED does not light - no current flows. I then take the lead out of the red socket and plug it into the yellow socket which allows up to 10 A. I switched the multimeter to the 10 A setting. The LED lights and the current registered as "0.01" A which is of course not very accurate, hence me wanting to use the 200 mA setting. Any idea why it's not letting me use the 200 mA setting? My guess is some sort of protection against too-high a current, but this protection should not be getting activated.

  2. #2
    Retired Administrator Norm's Avatar
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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    Is it possible the 200mA range on your meter is faulty or been damaged in some way.

    Norm

  3. #3
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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    Depending on a DMM model, the 200mA range setting is usually fused. Check the fuse.

    Bill

  4. #4

    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    Quote Originally Posted by Norm View Post
    Is it possible the 200mA range on your meter is faulty or been damaged in some way.
    That would be my guess too. I'd had two DMMs stop working on their mA ports. Once was definitely my fault - ran a >1A load through it by mistake (tried changing the fuse, but no effect - so likely damage to the circuitry). Second meter was a mystery (haven't tried changing the fuse, but I know I didn't subject it to anything unusual).

    It your meter has a continuity measuring feature (often audible), check to see if the port is actually working. If not, you could try swapping the fuse (they usually only cost a coupe of bucks).
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    *Flashaholic* fyrstormer's Avatar
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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    +1 on checking the fuse.

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    Flashaholic* Wrend's Avatar
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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    Quote Originally Posted by fyrstormer View Post
    +1 on checking the fuse.
    Yeah, it happens now and then, even if you think you know what you're doing (myself included).

  7. #7

    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    It could be the terminals have to be in a different location for 200mA than for 10A.

    Do you have a manual handy?

  8. #8
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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    No feed back from OP, which is curious. I'll close thread if he doesn't respond soon.

    Bill

  9. #9

    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    Yes, it was the fuse. Thanks very much for the responses. I forgot to report back after changing the fuse. I had the same problem and vaguely recalled solving it before so came back here. I've blown the fuse again!
    Last edited by seanspotatobusiness; 03-26-2014 at 02:54 AM.

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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    After all of this time the question was not asked, 'what brand, model DMM are we talking about"?

  11. #11
    *Flashaholic* fyrstormer's Avatar
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    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    (meh, nevermind)

  12. #12

    Default Re: Small current doesn't flow through multimeter set to 200 mA but does when set to

    It's a Precision Gold Academy PG 10B. I've had it since I was a kid; maybe 15 or more years. They still make them, it seems with very little change in appearance.

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