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

The 5 mm RGB LED, Common Anode, is a versatile light-emitting diode that combines red, green, and blue 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, Green, Blue (R-G-B)

1. Connect the Common Anode: Attach the second pin (Common Anode) to the positive voltage supply (e.g., 5V for Arduino projects).
2. Connect Resistors: Use current-limiting resistors (typically 220Ω to 330Ω) in series with each cathode (R, G, B) to prevent excessive current flow.
3. Control the Colors: Connect the cathodes (R, G, B) to ground through switches, transistors, or microcontroller pins (e.g., Arduino PWM pins) to control the brightness of each color.

• Resistor Selection: Choose appropriate resistors to limit current to 20 mA per LED. Use Ohm's Law (R = (V_supply - V_forward) / I) to calculate the resistor value.
• PWM Control: Use Pulse Width Modulation (PWM) to adjust the brightness of each LED and mix colors.
• Heat Management: Avoid exceeding the maximum power dissipation to prevent overheating.
• Pin Identification: The longest pin is the Common Anode. Use a multimeter if unsure about pin configuration.

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, Green, and Blue cathodes to Arduino PWM pins (e.g., 9, 10, 11) through 220Ω resistors.

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

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

void loop() {
  // Example: Cycle through colors
  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);
}

// Function to set RGB LED color
void setColor(int redValue, int greenValue, int blueValue) {
  analogWrite(redPin, 255 - redValue);   // Invert value for common anode
  analogWrite(greenPin, 255 - greenValue); // Invert value for common anode
  analogWrite(bluePin, 255 - blueValue);  // Invert value for common anode
}

1. LED Not Lighting Up:

   • Check the pin connections and ensure the Common Anode is connected to the positive voltage supply.
   • Verify that the resistors are correctly placed and not too high in value.
   • Ensure the Arduino or power source is functioning properly.

2. Incorrect Colors or No Color Mixing:

   • Verify the pin order (R-G-B) and ensure the correct cathodes are connected to the appropriate pins.
   • Check the PWM values in the code to ensure proper brightness levels.

3. LED Flickering:

   • Ensure stable power supply and proper grounding.
   • Verify that the PWM frequency is appropriate for smooth dimming.

4. Overheating:

   • Ensure current-limiting resistors are used and that the current does not exceed 20 mA per LED.

• Q: Can I use this LED without a microcontroller?

  • A: Yes, you can use switches or potentiometers to control the cathodes manually.

• Q: What happens if I connect the Common Anode to ground?

  • A: The LED will not function, as the anode must be connected to a positive voltage supply.

• Q: Can I power this LED directly from a 9V battery?

  • A: Yes, but you must use appropriate resistors to limit the current for each LED.

This documentation provides all the necessary details to effectively use the 5 mm RGB LED, Common Anode, in your projects.