precision mV source

Discussion in 'General Electronics Chat' started by strantor, Feb 22, 2011.

  1. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
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  2. strantor

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    yep, Twice as much
     
  3. eblc1388

    Senior Member

    Nov 28, 2008
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    A mV voltage source can be built using a standard voltage source and a resistive voltage divider.

    If one keeps the resistance of one leg of the divider very low, say 0.1Ω, then the change of voltage due to the impedance of the external loading can usually be neglected.

    Say if you have a 1V reference source, a 99.9Ω resistor and a 0.1Ω resistor would give a 1mV reference source.
     
  4. strantor

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    Thanks eblc1388,
    The thing is that this is for a load cell that if not calibrated properly could result in death. I don't want to do anything, no matter how logically sound or time proven, that could be looked back on by my superiors (who don't know anything about resistive voltage dividers) as "cutting corners" or "neglectful" - not my words, but the possible future words of others. I am looking for a purpose-built mV source with a legitimate certificate of calibration. it's one of those "cover your own ass" situations. follow the calibration procedure to the "T", using calibrated calibration equipment and they can't point the finger at you.

    I guess I should have mentioned that in the original post. sorry.
     
  5. eblc1388

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    If that is the case, I don't see you have any other choices other than to buy/lease a proper mV source, with certified calibration, to do your job.
     
  6. strantor

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    Yes, I definitely need the proper source with certified calibration. I was looking for some recommendations on a relatively inexpensive one. I think you gave me something better than that; the idea of leasing. I never considered that. Thanks again for yet another idea!
     
  7. someonesdad

    Senior Member

    Jul 7, 2009
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    There are numerous commercial products for such a task. For example, look at the Fluke 715. A kilobuck for such a device is trivial if there's the risk of injury or property damage.
     
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  8. Jaguarjoe

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    Apr 7, 2010
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    What he said
     
  9. Markd77

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    What if you make the divider and measure it with a calibrated meter?
     
  10. aegistalons

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    Feb 12, 2011
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    I think he wants something off the shelf and more plug and play. Does the company that sells the strain gauge not make an appropriate voltage source? Also look at National Instruments, they should probably have something like that.
     
  11. strantor

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    Yessir I agree. I guess I'll just have to suck it up.

    I browsed the NI website and they have alot of intriguing stuff there, but looks like it's all rack mount modular cards that go with their systems. I didn't see any standalone handheld stuff there. maybe I'm missing something.

    Perfectly good plan there, but it deviates from the established procedure which could come back to bite me in the rear I fear. Being 'not an engineer' I am a slave to the S.O.P.

    That's it, I'm going to college. This is b.s.
     
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