Does this LED need certain resistors per color?

Magnet wire resistors, enough to make any engineer scream.
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Joined: Wed Feb 15, 2017 3:23 am

Does this LED need certain resistors per color?

Post by Whitelight »

I have an arduino kit (5v) and instead of just following their simple instructions I want to know why they are using certain resistors for their RGB LED's.

The RGB LED that comes with this is identical to this one:LED Indication HLMP-EG24-PS000. And I'm assuming the forward voltage and current is the same.

The directions call for three 220-ohm resistors, but is that necessary? My math tells me that Red needs a 100-ohm and the Green & Blue need 160-ohm's. Won't using more resistance decrease the luminosity of the LED?

Or maybe the resistors have something to do with the affect they are trying to achieve with the LED? Here's what the book states, which I don't really understand:

"By creating a voltage difference between the cathode and voltage coming out of the Arduino's PWM pins (which are connected to the anodes through 220-ohm resistors), you'll cause the LED to fade between its three colors."

Do the resistors have anything to do with this fading, or isn't it just the PWM controlling that?
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Post by April155 »

As you metioned in your post, I think you should have a read of the datasheet of HLMP-EG24-PS000, and here it the datasheet: ... -PS000.pdf

Hope this can help you! :D
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