LM3914 - Expanded Scale Voltmeter - Help!

Discussion in 'General Electronics Chat' started by joe426, Jan 15, 2012.

  1. joe426

    Thread Starter Active Member

    Aug 11, 2009
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  2. bertus

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    Apr 5, 2008
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    Hello,

    Did you download the datasheet?
    On page 9 there is an example how to expand the range.

    Bertus
     
  3. Jony130

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    Feb 17, 2009
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    What is you supply voltage?
     
  4. joe426

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    Aug 11, 2009
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    Yes, I've thoroughly looked at the documents I linked to above. They're really poorly written in my opinion and I'm having trouble following them (hence why I asked for help).

    I have two available rails. ~9v and 5v.
     
  5. Dippo

    New Member

    Oct 24, 2011
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    Dave Jones from EEVBlog made a really great tutorial about a battery tester using a LM3914. It's on Youtube.
    Link.
     
  6. joe426

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    Aug 11, 2009
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    Yeah, I linked to that video in my original post. He does a good job overall, but is still confusing about customizing a range.

    Isn't there a simple set of equations with resistor values? I don't see why this is so difficult. :confused:
     
  7. bertus

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  8. Jony130

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    This circuit should do the job
     
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  9. joe426

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    Aug 11, 2009
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    It will work for 4.25 to 5v? Is that what you're saying?
     
    Last edited: Jan 17, 2012
  10. Jony130

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    Yes, It will work from 4.25V to 5V As you mention in your first post.
    But you can easily adjust the range by using a potentiometer.
     
  11. joe426

    Thread Starter Active Member

    Aug 11, 2009
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    What would the resistor values need to be if the range was .5 to 3 volts?

    Thank you!
     
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