How to Use 5 mm RGB LED, Common Anode (R-B-G Pin Order): Examples, Pinouts, and Specs

The 5 mm RGB LED, Common Anode, is a versatile light-emitting diode that combines red, blue, and green LEDs into a single package. This component allows users to create a wide range of colors by adjusting the intensity of each LED. The "common anode" configuration means that all three LEDs share a single positive terminal, while the negative terminals for each color are controlled individually.

• Decorative lighting and displays
• Status indicators
• DIY electronics projects
• Color-mixing experiments
• Arduino and microcontroller-based projects

• Package Size: 5 mm diameter
• Configuration: Common Anode
• Forward Voltage:
  • Red: 2.0V - 2.4V
  • Green: 3.0V - 3.4V
  • Blue: 3.0V - 3.4V
• Forward Current: 20 mA (per color)
• Maximum Power Dissipation: 75 mW (per color)
• Viewing Angle: 20° - 30°
• Pin Order: Common Anode, Red, Blue, Green (from longest to shortest pin)

1. Identify the Pins: The longest pin is the common anode, while the other three pins correspond to the red, blue, and green cathodes (in that order).
2. Connect the Common Anode: Attach the common anode pin to the positive voltage supply (e.g., 5V).
3. Use Current-Limiting Resistors: Connect a resistor (typically 220Ω to 330Ω) in series with each cathode to limit the current and prevent damage to the LEDs.
4. Control the Cathodes: Use switches, transistors, or microcontroller GPIO pins to control the cathodes and adjust the brightness of each color.

• Resistor Selection: Choose appropriate resistors to limit the current to 20 mA per LED. Use Ohm's Law to calculate the resistor value:
  ( R = \frac{V_{supply} - V_{forward}}{I_{forward}} )
• PWM for Color Mixing: Use Pulse Width Modulation (PWM) to control the brightness of each LED and achieve smooth color transitions.
• Heat Management: Avoid exceeding the maximum power dissipation to prevent overheating.
• Pin Order: Double-check the pin order (Common Anode, Red, Blue, Green) to avoid incorrect connections.

Below is an example of how to connect and control the 5 mm RGB LED using an Arduino UNO.

• Connect the common anode pin to the 5V pin on the Arduino.
• Connect the red, blue, and green cathodes to Arduino digital pins 9, 10, and 11, respectively, through 220Ω resistors.

// Define the pins for the RGB LED
const int redPin = 9;   // Red cathode connected to pin 9
const int bluePin = 10; // Blue cathode connected to pin 10
const int greenPin = 11; // Green cathode connected to pin 11

void setup() {
  // Set the RGB LED pins as outputs
  pinMode(redPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
  pinMode(greenPin, OUTPUT);
}

void loop() {
  // Example: Display red color
  analogWrite(redPin, 255);  // Full brightness for red
  analogWrite(bluePin, 0);   // Turn off blue
  analogWrite(greenPin, 0);  // Turn off green
  delay(1000);               // Wait for 1 second

  // Example: Display green color
  analogWrite(redPin, 0);    // Turn off red
  analogWrite(bluePin, 0);   // Turn off blue
  analogWrite(greenPin, 255); // Full brightness for green
  delay(1000);               // Wait for 1 second

  // Example: Display blue color
  analogWrite(redPin, 0);    // Turn off red
  analogWrite(bluePin, 255); // Full brightness for blue
  analogWrite(greenPin, 0);  // Turn off green
  delay(1000);               // Wait for 1 second

  // Example: Display white color (all LEDs on)
  analogWrite(redPin, 255);  // Full brightness for red
  analogWrite(bluePin, 255); // Full brightness for blue
  analogWrite(greenPin, 255); // Full brightness for green
  delay(1000);               // Wait for 1 second
}

1. LED Does Not Light Up:

   • Cause: Incorrect pin connections or missing resistors.
   • Solution: Verify the pin connections and ensure resistors are in place.

2. LED Flickers or is Dim:

   • Cause: Insufficient current or incorrect resistor values.
   • Solution: Check the resistor values and ensure the power supply provides adequate current.

3. Colors Appear Incorrect:

   • Cause: Pins connected in the wrong order.
   • Solution: Double-check the pin order (Common Anode, Red, Blue, Green).

4. Overheating:

   • Cause: Excessive current through the LEDs.
   • Solution: Use appropriate resistors to limit the current to 20 mA per LED.

• Can I use this LED with a 3.3V power supply?
  Yes, but you may need to adjust the resistor values to ensure proper current limiting.

• How do I create custom colors?
  Use PWM to adjust the brightness of each LED. By mixing different intensities of red, blue, and green, you can create a wide range of colors.

• What happens if I connect the common anode to ground?
  The LED will not function correctly, as the common anode must be connected to a positive voltage source.

This concludes the documentation for the 5 mm RGB LED, Common Anode.