How to Use LED: Two Pin (red) - Long Pins: Examples, Pinouts, and Specs

The Two Pin Red LED is a light-emitting diode that emits bright red light when powered. It features two pins: a longer pin (anode) and a shorter pin (cathode), making it easy to identify polarity and connect in circuits. The long pins are particularly useful for breadboard prototyping and soldering applications. This LED is widely used in electronics for visual indicators, status lights, and decorative lighting.

• Power and status indicators in electronic devices
• DIY electronics and prototyping
• Signal and warning lights
• Decorative and ambient lighting
• Educational projects and Arduino-based designs

Below are the key technical details for the Two Pin Red LED:

The Two Pin Red LED has the following pin configuration:

1. Identify the Pins: The longer pin is the anode (positive), and the shorter pin is the cathode (negative).

2. Connect to Power:

   • Connect the anode to the positive voltage source through a current-limiting resistor.
   • Connect the cathode to the ground (GND).

3. Choose a Resistor: To prevent damage, use a resistor to limit the current. Calculate the resistor value using Ohm's Law: [ R = \frac{V_{supply} - V_f}{I_f} ]

   • (V_{supply}): Supply voltage
   • (V_f): Forward voltage of the LED (1.8V to 2.2V)
   • (I_f): Desired forward current (e.g., 20mA)

   For example, with a 5V supply and a forward voltage of 2V: [ R = \frac{5V - 2V}{0.02A} = 150\Omega ]

4. Insert into Circuit: Place the LED and resistor in series, ensuring correct polarity.

The Two Pin Red LED can be easily connected to an Arduino UNO for control. Below is an example of blinking the LED:

• Connect the anode (long pin) to Arduino digital pin 13 through a 220Ω resistor.
• Connect the cathode (short pin) to the Arduino GND pin.

// LED Blink Example for Two Pin Red LED
// Connect the LED anode to pin 13 through a 220Ω resistor
// Connect the LED cathode to GND

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

• Always use a current-limiting resistor to avoid damaging the LED.
• Verify the polarity before powering the circuit.
• Avoid exceeding the maximum current rating (30mA) to ensure longevity.

1. LED Does Not Light Up

   • Cause: Incorrect polarity.

   • Solution: Ensure the anode is connected to the positive voltage and the cathode to GND.

   • Cause: No current-limiting resistor or incorrect resistor value.

   • Solution: Use a resistor with the correct value (e.g., 150Ω for 5V supply).

2. LED is Dim

   • Cause: Insufficient current.
   • Solution: Check the resistor value and ensure it allows enough current (e.g., 20mA).

3. LED Burns Out

   • Cause: Excessive current.
   • Solution: Use a resistor to limit the current to 20mA or less.

4. Flickering LED

   • Cause: Unstable power supply or loose connections.
   • Solution: Check the power source and ensure all connections are secure.

Q: Can I connect the LED directly to a 3.3V or 5V power source?
A: No, you must use a current-limiting resistor to prevent excessive current from damaging the LED.

Q: What happens if I reverse the polarity?
A: The LED will not light up, but it will not be damaged unless reverse voltage exceeds its maximum rating (typically 5V).

Q: Can I use this LED with a PWM signal?
A: Yes, the LED can be dimmed or controlled using a PWM signal from a microcontroller like an Arduino.

Q: How do I calculate the resistor value for a different supply voltage?
A: Use the formula (R = \frac{V_{supply} - V_f}{I_f}), where (V_f) is the forward voltage and (I_f) is the desired current.

By following this documentation, you can effectively use the Two Pin Red LED in your electronic projects!