Boy do I feel silly, Mini 2 wire Volt meter from adafurit can read a Negative voltage.

Discussion in 'General Electronics Chat' started by 64C113M Abe., Oct 3, 2016.

  1. 64C113M Abe.

    Thread Starter New Member

    Sep 13, 2016
    14
    0
    I was stumped for a while, and thought I would share this in case someone else is stumped.

    https://www.adafruit.com/products/460

    For the longest while, I thought you needed a special voltmeter to read a negative voltage. It never dawned on me that the simplest way to get this voltmeter to read negative was to reverse the direction of the leads meaning you put black to your negative supply and red to your ground.

    Yeah maybe you don't have the minus telling you that it is negative but if you label it accordingly you'll know.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,429
    3,360
    In the same vein, how does one create a -9V supply from a standard 9V PP3 battery?
     
    DickCappels likes this.
  3. 64C113M Abe.

    Thread Starter New Member

    Sep 13, 2016
    14
    0
    If your using the standard clip, once again swap the leads.

    I haven't tested this yet, but I wonder if this will work with a 3 lead mini voltmeter.
     
  4. HW-nut

    Member

    May 12, 2016
    45
    11
    If you need +/- supplies, use a switch capacitor voltage inverter.
     
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