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Wiring different colored LEDs to power source

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  • Member since
    January 2002
  • From: Loudonville, NY
  • 762 posts
Wiring different colored LEDs to power source
Posted by Benjamin Maggi on Wednesday, March 31, 2021 1:48 PM

I found some colored (red,yellow,green,blue,orange) pre-wired 0402 LEDs online. They come with red and black wires for each. I think that they will work for my HO scale Christmas light project. As I understand it, different colored LEDs run on different voltages and if you give them too much bad things happen!

I was thinking of taking all the RED LEDs and connecting all the black (-) wires together, and all the red (+) wires together and then joinging those two connections to a 1.5v battery. I would do the same for the Orange, Yellow, Green and Blue LEDs. It takes 5 batteries, but that is okay as this is just for a temporary display. However, is there an easier way? 

Could I take ALL the red (+) wires from all the different colored LEDs and connect them together, and all the black (-) wires from all the LEDs and wire them together? And then power that with a 1.5 volt battery?

Thanks. Electrical theoy isn't my speciality.

Modeling the D&H in 1984: http://dandhcoloniemain.blogspot.com/

  • Member since
    January 2009
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Posted by RR_Mel on Wednesday, March 31, 2021 2:28 PM

Remember LEDs are current devices not voltage.  I would use a resistor in series from a power supply to set the current of the various colored LEDs for wanted brightness.  You didn’t mention the quantity of 0402s.  Say the Red draws 2ma at preferred brightness, you would multiply the current by the quantity (say 10 paralleled) then calculate the resistor for 20ma.

Each color will be a different current.
 

Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    October 2006
  • From: Western, MA
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Posted by richg1998 on Saturday, April 3, 2021 11:00 AM

Get your multimeter out. LED’s are usually rated at 20ma max.

 

http://www.trainelectronics.com/Meter_Workshop/index.htm

 

 

 Rich

 

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    December 2004
  • From: Bedford, MA, USA
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Posted by MisterBeasley on Saturday, April 3, 2021 2:18 PM

I built a signal bridge with a lot of red, green and yellow LEDs.  I used a fixed DC power supply and resistors.

My circuit used parallel wiring, and I found that a meter showed it was getting voltage as it should, but some of the LEDs would not light.  Apparently the internal resistance of different colored LEDs is different enough that one color would "steal" all the power from the others.  

My solution was to change to series wiring.  This worked perfectly.

It takes an iron man to play with a toy iron horse. 

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