Why does the forward voltage and voltage drop differ between different colors of LEDs? - Quora
How do I calculate what resistors I need for RGB LEDs with 3.7V? - Electrical Engineering Stack Exchange
At minimum you should know what resistor you need for which colour of led, what should be the supply voltage, what is expected f… | Electronics basics, Led, Rgb led
LED at Lower Voltage? - Project Guidance - Arduino Forum