An RGB LED has 4 pins, one for each color (Red, Green, Blue) and a common cathode. It has tree different color-emitting diodes that can be combined to create all sorts of color! Any color is possible depending on how bright each diode is.
For those beginning to learn about robotics, particularly in the area of building circuits, you may have come across the question of how to change the brightness of a LED, without having to keep switching parts. Quite simply, the solution to this issue is a potentiometer.
In this example you will learn how to fade an LED by using analogWrite() function. AnalogWrite uses pulse width modulation (PWM), turning a digital pin on and off very quickly, to create a fading effect.