🔴 PART 8 — RGB LED

What does RGB stand for?

R = Red

G = Green

B = Blue

What is an RGB LED?

An RGB LED contains three LED channels — red, green and blue — inside one package.

How can an RGB LED produce different colours?

By changing the intensity of the red, green and blue channels and mixing their light.

How can PWM be used with an RGB LED?

PWM controls the brightness/intensity of each colour channel.

For example:

Red = 255

Green = 0

Blue = 0

→ Bright red.

What is a common-cathode RGB LED?

An RGB LED where the three LED channels share a common cathode/negative connection, which is connected to GND.

How many possible intensity values can each RGB channel have?

256 values, from:

0–255

How many possible RGB combinations are there theoretically?

Each channel has 256 possibilities:

$256\times256\times256$ $=\boxed{16,777,216}$

So there are approximately 16.7 million possible RGB combinations.

Why does an RGB LED need a resistor for each colour channel?

Each LED channel needs its current controlled to prevent excessive current.

So typically there is one current-limiting resistor per channel.