Wiring different colored LEDs to power source

[MisterBeasley]

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.

[richg1998]

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

 

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

 

 

 Rich

 

[RR_Mel]

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


 
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[Benjamin Maggi]

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.