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multimeters

Discussion in 'Electronic Basics' started by [email protected], Nov 28, 2007.

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  1. Guest

    I have a question about multimeters and was wondering if ne one could
    answer a question for me.
    I was curious if it was more important if the meter has an autoranging
    function or a true RMS function. I need to purchase one and I don't
    know which is more important to have.
     
  2. Jamie

    Jamie Guest

    there both important how ever, having a true RMS meter is very
    important also one that is rated in the CAT II and III.
    The Auto Ranging is good if you make a mistake. Some lower meters
    are not forgiving. If you're careful, you'll be ok.
     
  3. Guest

    8-function, 20-range multimeter offers true RMS readings for accurate
    voltage, current and temperature. CAT III-600V rating. Audible and
    visual warnings to help improper test lead input.

    11-function, autoranging, voltage current temp, CAT II-600V, but no
    true RMS readings.

    just curious of ur opinion on which one would be better. thanks
     
  4. John Fields

    John Fields Guest

     
  5. Guest

    So go with the one with the true RMS?
     
  6. John Fields

    John Fields Guest

     
  7. Jamie

    Jamie Guest

    if you have to select from those 2, Take the 8 function, 20 range with
    true RMS.
     
  8. Guest

    Well I solved the problem.... I bought one that has the true RMS
    reading function, the CAT III-600V and it has a built-in InfraRed
    thermometer. So I think this one sould do it.
     
  9. Guest

     
  10. Guest

     
  11. Technically speaking, the True RMS function is more important.
    Without True RMS, you can't measure all AC signals as accurately. But
    lack of autoranging does not compromise the actual meters performance.

    The two are not mutually exclusive, get one with both!
    A Meterman 37XR/38XR is True RMS and autoranging, and it top quality
    at a reasonable price.
    If you are really strapped for cash, get a cheaper brand with both.
    Autoranging is a must-have, so much more convenient than manual
    ranging.

    There is really no reason to buy a manual range meter these days,
    Autorange is cheap and readily available.

    Dave.
     
  12. So what's the brand and model of the one you bought?

    Dave.
     
  13. Jamie

    Jamie Guest

    http://www.testequipmentdepot.com/extech/clampmeters/ex800series.htm

    Ex830, 1000 Amp Clamp AC/DC with all the goodies

    Good tool box toss around meter.., It also has thermo pointer in it.

    I wouldn't do anything precision with it how ever, it's good for basic
    industrial probing around. It's also great for HVAC guys, it just about
    has it all in one..
     
  14. Phil Allison

    Phil Allison Guest

    "David Lying Jones "

    ** That is more D L Jerkoff self opinionated bollocks.

    There is nothing inherently more "accurate" about measuring / computing the
    rms value of an AC wave.

    Non " rms " multimeters respond to the "average rectified value" of the AC
    wave - scaled up to display the exact rms value with sine wave signals. As
    the vast majority of AC voltages and currents encountered in ELECTRICAL work
    have close to sine wave shape - this is perfectly good method.

    The peak value and /or the average rectified value of a non-sine AC wave
    are more likely to be important to know than the more obscure " true rms"
    value. If the wave shape matters, then you need a scope to look at it.

    PLUS - the "true rms" function of budget multimeters has *woefully narrow*
    measurement bandwidth ( often < 500Hz ) which * INHERENTLY * spoils the
    supposed accuracy of all readings of non sine wave forms - which typically
    contain harmonics to well beyond the accurate measurement range of such
    multimeters.


    ** It sure as hell compromises the operator in most service situations.




    ....... Phil
     
  15. Eeyore

    Eeyore Guest

    Autoranging is invaluable.

    True RMS is nice but hardly necessary for most electronics and certainly not for
    a beginner. It's also expensive. Just be aware that most meters indicate average
    current not RMS.

    Graham
     
  16. Eeyore

    Eeyore Guest

    Ignore Jamie's nonsense.

    He's not very experienced in electronics but has a big mouth and can't resist
    talking about stuff he doesn't understand.

    Graham
     
  17. T

    T Guest

    For my purposes I didn't need anythign special. I picked up a DMM at
    Radio Shack for $29 Catlog number 22-813.

    It does auto-range for AC and DC voltage.

    The only gripe I have is the way the leads plug into the unit. They can
    come loose very easily.
     
  18. That's unreliable and potentially dangerous.

    http://www.radioshack.com/product/i...uctId=2103176&support=support&tab=custRatings
    Not exactly glowing reviews.

    Do yourself a favour and toss it in the bin.

    Dave.
     
  19. T

    T Guest

  20. T

    T Guest

    I note that most of the bad reviews have to do with blown fuses on the
    unit. One of them was ridiculous, the end had broken off where the leads
    connect and the reviewer didn't know how to fix it? Come on.

    I have no problem opening it up to fix it should I have to do so.
     
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