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Topic: Project 4 - Color Mixing Lamp - RGB LED resistor pacement (Read 780 times) previous topic - next topic

jaykeystk

Hi  :smiley:


The LEDs need a resistor to get the voltage down to an acceptable level, and it does not matter if the resistor is on the anode side or if its on the cathode side, as long as it is in series with the LED right?

Then why are there 3x 220 Ohm resistors between the RGB LED and Digital PWM pins 9,10 and 11. Could there not just be 1 instead? between the cathode and ground?  Would that not have the exact same effect?




 :)



CrossRoads

"LEDs need a resistor to get the voltage current down"

If you are going to have all 3 LEDs on at one time, being controlled from 3 pins, then you need 3 resistors.
If you could guarantee that only 1 LED would be on at any time, then 1 resistor in series with the common pin would be acceptable.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

jaykeystk

Thank you CrossRoads ! :-)

Kinda makes sense when you say it :-)

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