3. Common anode

The RGB LEDs we are using have a common anode.


There is one lead going to the negative connection of each of the single LEDs within the package and a single lead that is connected to all three positive sides of the LEDs.

The common anode of the LED package is longest of the four leads. This lead will be connected to 5V.

Each LED inside the package requires its own current limiting resistor. The three negative leads of the LEDs (one red, one green and one blue) are connected to Arduino output pins using these resistors.