PROJECT 07 – RGB LED

INTRODUCTION

An RGB LED is really three LEDs inside a single device – one red, one green and one blue.

It has four legs (pins). The longest leg is common to all LEDs inside. Some models use a common anode (positive) and some use a common cathode (negative) pin. See the diagram below.

The legs R,G and B need to be connected to a resistor and then to either Vcc or ground (the opposite of the common leg).

The resistor values should not be the same. The red LED needs a lower voltage drop across it so the resistance should be higher than for the other two colours.

For use with a 5 volt source, the red leg's resistor should be about 300 ohms while the other two colours should each have a resistor of about 180 ohms. Of course, you can try other higher values and will likely have success.

WORK

Connect an RGB LED to a power source and resistors. Make sure you are comfortable with how it works.

To get 4/5, you need to be ready to set the colour to what Mr. Campeau asks for.

To get 5/5, you need to use a potentiometer on each LED colour leg to gradually adjust the colours manually. This is pretty cool!