help with a meter of sorts

Discussion in 'General Electronics Chat' started by atwinda, Mar 3, 2007.

  1. atwinda

    Thread Starter New Member

    Mar 3, 2007
    1
    0
    I know that this is probably very simple for some folks here, so that is why I am coming to you guys!

    I'm trying to make a simple meter using a pot and led output. I have 12v going to the pot, and what I don't understand is how I control the leds after that.. For simplicity's sake lets say I want to show 2v - 12v in even increments. The previous led can stay lit. So basically I want one led to come on at 2v, the next to come on at 4v, etc... I know I need to use resistors going to each led, but I don't know how to figure out what the value of the resistor should be.

    I've found a few diagrams floating around, but I'm not the most educated when it comes to reading electrical diagrams.

    thanks in advance!
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Search this site using "LM3914" as the search term. You will turn up numerous posts about this IC, which is made to do the metering you want.
     
  3. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Take a look at this device. LM3914 Datasheet

    There are several example circuits in the datasheet. You can also google for example circuits.

    It is available from digikey for less than 3 dollars.

    hgmjr
     
  4. electronics wiz

    Active Member

    Mar 15, 2007
    54
    0
    you can use compartors if you want.
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Certainly a series of window comparators would work - that's how the LM3914 works it's voodoo. It would be more effort and more expense.
     
  6. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    atwinda appears to be gone with the winda. He dropped the post and has not return since then.
    hgmjr
     
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