Arduino UNO LED Connection Guide

Step-by-step setup and code to blink your first LED

🔌 Components Required

Component	Quantity
Arduino UNO	1
LED (Light Emitting Diode)	1
220Ω Resistor	1
Breadboard	1
Jumper Wires	2
USB Cable	1

📋 Step-by-Step Instructions

1. 1 Place the LED Insert the LED into the breadboard.
   Note: Longer leg = Anode (+), Shorter leg = Cathode (−)
2. 2 Connect Pin 13 to Resistor Connect one end of the 220Ω resistor to Digital Pin 13 of the Arduino UNO.
3. 3 Connect Resistor to LED Connect the other end of the resistor to the long leg (Anode +) of the LED.
   Arduino Pin 13 → 220Ω Resistor → LED Long Leg (+)
4. 4 Connect LED to GND Connect the short leg (Cathode −) of the LED to an Arduino GND pin.
   LED Short Leg (−) → Arduino GND
5. 5 Connect USB Plug the Arduino UNO into your computer using the USB cable.
6. 6 Upload the Program Open the Arduino IDE, paste the code below, and click Upload.
7. 7 Observe The LED will cycle: ON (1s) → OFF (1s) → Repeat.

⚠️ Important Safety Note: Never connect an LED directly to Pin 13 without a resistor. Always use a 220Ω or 330Ω current-limiting resistor to protect both the LED and your board.

📐 Circuit Diagram

Arduino UNO

Digital Pin 13
      │
      │
   [220Ω]
      │
      │
 LED Long Leg (+)
      │
 LED Short Leg (−)
      │
      │
     GND
    

💻 Arduino Code

int LED = 13;

void setup() {
  pinMode(LED, OUTPUT);
}

void loop() {
  digitalWrite(LED, HIGH);
  delay(1000);

  digitalWrite(LED, LOW);
  delay(1000);
}