RGB LED

Overview

RGB LED (Red Green Blue Light Emitting Diode) — a single LED package containing three individual LED elements (Red, Green, Blue) that can be mixed to produce virtually any color in the visible spectrum. Available in Common Cathode and Common Anode configurations. Widely used in color indicators, mood lighting, status displays, decorative lighting, Arduino/ESP32 color projects, and visual feedback systems. Available in 5mm through-hole package.

Specifications

Parameter	Value
Type	RGB LED (Red + Green + Blue)
Package	5mm Through-hole
Configuration	Common Cathode (or Common Anode)
Forward Voltage (Red)	1.8V – 2.2V
Forward Voltage (Green)	2.8V – 3.4V
Forward Voltage (Blue)	2.8V – 3.4V
Forward Current	20mA per channel (max)
Luminous Intensity (Red)	800 – 1500mcd
Luminous Intensity (Green)	1000 – 2000mcd
Luminous Intensity (Blue)	800 – 1500mcd
Viewing Angle	30°
Operating Temperature	-40°C to +85°C
Lead Spacing	2.54mm (breadboard compatible)

Pin Configuration

Common Cathode (Most Common)

Pin	Position	Description
R	Pin 1 (left)	Red anode
GND	Pin 2 (longest)	Common cathode (GND)
G	Pin 3	Green anode
B	Pin 4 (right)	Blue anode

Common Anode

Pin	Position	Description
R	Pin 1 (left)	Red cathode
VCC	Pin 2 (longest)	Common anode (VCC)
G	Pin 3	Green cathode
B	Pin 4 (right)	Blue cathode

Features

• 3-in-1 package — Red, Green, Blue in single 5mm LED
• Full color mixing — 16 million+ colors via PWM
• Common cathode and anode variants available
• Breadboard friendly — 2.54mm standard pitch
• 5mm standard package — fits all standard LED holders
• Low power — 20mA max per channel
• Wide viewing angle — 30° viewing cone
• PWM compatible — smooth color transitions with microcontrollers
• Easy to use — simple resistor + GPIO wiring

Required Resistors

Always use current limiting resistors to protect LED and microcontroller!

Color	Supply 5V	Supply 3.3V
Red	150Ω	56Ω
Green	100Ω	33Ω
Blue	100Ω	33Ω

Formula: R = (VSupply - VForward) / IForward Example Red @ 5V: R = (5V - 2V) / 0.02A = 150Ω

Wiring (Common Cathode — Arduino)

RGB LED	Arduino
R (Pin 1)	150Ω → Pin 9 (PWM)
GND (Pin 2)	GND
G (Pin 3)	100Ω → Pin 10 (PWM)
B (Pin 4)	100Ω → Pin 11 (PWM)

Wiring (Common Cathode — ESP32)

RGB LED	ESP32
R (Pin 1)	56Ω → GPIO25
GND (Pin 2)	GND
G (Pin 3)	33Ω → GPIO26
B (Pin 4)	33Ω → GPIO27

Arduino Code — Basic Colors

int redPin   = 9;
int greenPin = 10;
int bluePin  = 11;

void setColor(int r, int g, int b) {
  analogWrite(redPin,   r);
  analogWrite(greenPin, g);
  analogWrite(bluePin,  b);
}

void setup() {
  pinMode(redPin,   OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin,  OUTPUT);
}

void loop() {
  setColor(255, 0,   0);   // Red
  delay(1000);
  setColor(0,   255, 0);   // Green
  delay(1000);
  setColor(0,   0,   255); // Blue
  delay(1000);
  setColor(255, 255, 0);   // Yellow
  delay(1000);
  setColor(0,   255, 255); // Cyan
  delay(1000);
  setColor(255, 0,   255); // Magenta
  delay(1000);
  setColor(255, 255, 255); // White
  delay(1000);
  setColor(0,   0,   0);   // Off
  delay(1000);
}

Arduino Code — Rainbow Fade

int redPin   = 9;
int greenPin = 10;
int bluePin  = 11;

void setColor(int r, int g, int b) {
  analogWrite(redPin,   r);
  analogWrite(greenPin, g);
  analogWrite(bluePin,  b);
}

void wheel(int pos) {
  if (pos < 85) {
    setColor(pos * 3, 255 - pos * 3, 0);
  } else if (pos < 170) {
    pos -= 85;
    setColor(255 - pos * 3, 0, pos * 3);
  } else {
    pos -= 170;
    setColor(0, pos * 3, 255 - pos * 3);
  }
}

void setup() {
  pinMode(redPin,   OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin,  OUTPUT);
}

void loop() {
  for (int i = 0; i < 256; i++) {
    wheel(i);
    delay(10);
  }
}

ESP32 Code (LEDC PWM)

#define RED_PIN   25
#define GREEN_PIN 26
#define BLUE_PIN  27

void setColor(int r, int g, int b) {
  ledcWrite(0, r);
  ledcWrite(1, g);
  ledcWrite(2, b);
}

void setup() {
  ledcSetup(0, 5000, 8); ledcAttachPin(RED_PIN,   0);
  ledcSetup(1, 5000, 8); ledcAttachPin(GREEN_PIN, 1);
  ledcSetup(2, 5000, 8); ledcAttachPin(BLUE_PIN,  2);
}

void loop() {
  setColor(255, 0,   0);   delay(500); // Red
  setColor(0,   255, 0);   delay(500); // Green
  setColor(0,   0,   255); delay(500); // Blue
  setColor(255, 255, 255); delay(500); // White
}

Common Color Mixing Reference

Color	Red	Green	Blue
Red	255	0	0
Green	0	255	0
Blue	0	0	255
Yellow	255	255	0
Cyan	0	255	255
Magenta	255	0	255
White	255	255	255
Orange	255	165	0
Pink	255	20	147
Purple	128	0	128
Off	0	0	0

Common Cathode vs Common Anode

Feature	Common Cathode	Common Anode
Common pin	GND	VCC
Turn ON	HIGH signal	LOW signal
Arduino default	✅ Easier	Inverted logic
Identification	Longest pin → GND	Longest pin → VCC

⚠️ Important Notes

• ALWAYS use resistors — never connect LED directly to GPIO or 5V
• Identify type first — Common Cathode vs Common Anode before wiring
• Max 20mA per channel — exceeding damages LED and microcontroller
• PWM for color mixing — digitalWrite only gives ON/OFF, use analogWrite
• Longest lead — always the common pin (cathode or anode)
• 3.3V systems — use smaller resistors (56Ω red, 33Ω green/blue)
• Do not exceed total 40mA from any Arduino/ESP32 GPIO pin

Applications

• Status indicator lights
• Color-coded alerts and notifications
• Mood and ambient lighting
• RGB display backlight
• Color mixing experiments
• Traffic light simulation
• Arduino and ESP32 learning projects
• Interactive art and displays
• Smart home color indicators
• Robot eye and expression displays
• Decorative electronics projects