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Wiring in an LED light

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  • Member since
    April 2011
  • From: About 20 minutes from IRM
  • 430 posts
Wiring in an LED light
Posted by CGW121 on Wednesday, January 11, 2017 9:17 AM

Have the resister etc but the led has a long lead and a shorter one. Which one is positivewhich one is negative? For what its worth it is a Lifelike f3, Dcc of course.

                                       Mike

 

  • Member since
    December 2016
  • 168 posts
Posted by speedybee on Wednesday, January 11, 2017 9:48 AM

The standard polarity for an led is positive long, negative short. That said, you can always test it. If it works, you've got it right, and if it doesn't work, you've got it wrong. You won't damage it by applying the voltage in reverse.

Just be certain that you have the correct resistor. Too low resistance and the led will burn out very quickly, eg immediately.

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    June 2003
  • From: Northeast OH
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Posted by tstage on Wednesday, January 11, 2017 9:52 AM

Mike,

Here's a helpful diagram:

The longer lead is the anode (+); the shorter, the cathode (-).  Your colored wires (e.g. white & yellow) will always go on the cathode and the blue (common) wire on the anode.

The resistor can go on either the anode or cathode.  For consistency I always put it on the cathode but, again, it doesn't matter.

Two other ways to differentiate between the anode and the cathode:

  • Interior: Anvil & post - The anvil (anode) is always smaller than the post (cathode)
  • Exterior: The LED bulb has a flat spot on the cathode side

Hope that helps...

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

  • Member since
    October 2006
  • From: Western, MA
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Posted by richg1998 on Wednesday, January 11, 2017 10:45 AM

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.

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