Led glowing after power off

Discussion in 'General Electronics Chat' started by bramswell, Dec 28, 2012.

  1. bramswell

    Thread Starter New Member

    Dec 28, 2012
    3
    0
    Hello

    I'm new to the forum, as you can see this is first post.

    I'm a newbie to electronics aswell so please be gentle with me

    I have googled my problem several times and not found a solution yet,

    My problem is that I have changed the leds in my car air conditioning control panel to blue as I couldn't really see the green original leds due to being a bit colour blind.

    So the problem I have is the new leds I soldered onto thecircuit board are brighter than the originals and when the power is off some of the leds glow and can stay on forsome time

    Is there a way to drop the power from the circuit to stop the leds glowing?

    Thanks for any help
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    You could try adding some resistor in series, like 100ohm or something similar.
     
  3. bramswell

    Thread Starter New Member

    Dec 28, 2012
    3
    0
    Will a resistor suck up the remaining power in the circuit?

    If this is the case would putting a
    resistor in parallel with the led work?

    I am assuming there are resistors on the circuit any way as it is fairly complex... To me anyway
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    Increasing the series resistance will decrease the brightness... But it sounds like they get stuck on for a time when they should switch off... And if so decreacing their brightness will let them stay on even longer!

    A resistor in parallel will make them turn off quicker, quickly enough to seem instant. However you will need to find what value does this by experiment. We have no information to even guess what value to start with.
     
  5. bramswell

    Thread Starter New Member

    Dec 28, 2012
    3
    0
    Thanks for the reply

    I only have 1k resistor at the present as they were for another project.
    So I will give that a try and order up some other values, I can't get any info about the circuit as Ford don't have diagrams for individual controls only vehicle wiring.
     
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