I want to make an 3x3 LED module that will be about 4 feet from the control board that provides 12v. Do I need to put the resistor on the 3x3 LED circuit board or can I put the resistor on the control board circuit board?

 

I want to make an 3x3 LED module that will be about 4 feet from the control board that provides 12v. Do I need to put the resistor on the 3x3 LED circuit board or can I put the resistor on the control board circuit board?

It doesn't matter where you put a series resistor. It can go on the +ve leg or the -ve leg, anywhere along the daisy chain.

 

Ditto. It could literally be a mile away and work fine. In that case the resistance of the wire would add to the resistor value, but distance per se is irrelevant.

 

I wouldn't flinch at the idea of a 100 foot distance. LEDs aren't very smart and they aren't very picky. They don't care about high frequencies or the small amount of inductance in the wires, only resistance. It's hard to imagine a wire that won't carry 10ma or 20 ma for 100 feet, but I could calculate one. Something around 30 gauge.

 

As long as it's just LED's- you don't specify what exactly you mean by "3 X 3 module"

 

The only consideration I would place is how easy it is to short something out... Place the resistor on the side where it helps lesson the chance of releasing magic smoke.

That would place the resistors closest to the controller.