Very low range on LM3914?

Discussion in 'General Electronics Chat' started by tracecom, Feb 13, 2014.

  1. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    Is it possible to set the total range on an LM3914 to .05V, with a low of .970V and a high of 1.020V? If it's not possible using the internal reference of 1.25V, would it be possible using two external references, one for the low end of .970V and the other for the high at 1.020V?

    Thanks.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    When you look at the internal diagram of the LM3914, you will see a string of resistors between the pins 4 and 6.
    Pin 6 determines the max value and 4 the min value.

    [​IMG]

    So a pot (ca.46K needed) from pin 7 (Vref) to pin 6 and a pot (ca. 194K needed) from pin 4 to ground might give you the range.
    The total resistance between pin 6 and 4 is about 10 K.

    Bertus
     
    Last edited: Feb 14, 2014
    tracecom likes this.
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