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Logan Cade
09-28-2008, 11:20 AM
Is there any advantage/disadvantage for running the resistor on the Anode or Cathode side in an LED circuit?

I’m playing around with RGB LED’s and you can get them either way, common Cathode or common Anode.

Obi-Dar Ke-Gnomie
09-28-2008, 11:48 AM
In theory, it doesn't matter. Wherever the resistor is in the circuit, it will limit current flow. However, for the sake of consistency, and because it "feels right" to do so, I always put the resistor before the LED.

Logan Cade
09-28-2008, 02:17 PM
Thanks Obi-Dar, that’s the way I was running mine because these RGB LED’s I’m playing with have a common Cathode.

I was curious if anyone had any negative effects running a potentiometer to adjust resistance on the Positive side (anode) that was eliminated running it on the Negative side (Cathode) using a common Anode RGB LED….stuff like sound issues, flickering, heat, lack of brightness…stuff like that.