Arduino UNO LED Wiring Guide

Interactive Step-by-Step Circuit Assembly

Step 1 of 7

Place the LED

Insert the LED into two separate terminal rows on your breadboard.

[ LED Component ] Longer leg = Anode (+) Shorter leg = Cathode (−)

Tip: Note down which breadboard row connects to the longer leg.

Step 2 of 7

Connect Pin 13 to Resistor

Attach one end of the 220Ω resistor into Digital Pin 13 on the Arduino board using a jumper wire (or directly).

[Arduino UNO] [Breadboard] Pin 13 ───────────────► [220Ω Resistor End A]

Step 3 of 7

Connect Resistor to LED

Connect the other end of the 220Ω resistor to the Anode (+) (longer leg) of the LED.

[Resistor End B] ────────► LED Long Leg (+ Anode)

Step 4 of 7

Connect LED to GND

Use a jumper wire to connect the Cathode (−) (shorter leg) of the LED to an Arduino GND pin.

LED Short Leg (− Cathode) ───(Black Wire)───► [Arduino GND]

⚠️ Warning: Do not skip the resistor! Connecting directly to Pin 13 without a 220Ω or 330Ω resistor can burn out the LED.

Step 5 of 7

Connect USB Cable

Plug the USB-A end into your computer and the USB-B end into your Arduino UNO to power the board.

[Computer USB Port] ═══════════════► [Arduino USB Jack]

Step 6 of 7

Upload Code

Open the Arduino IDE, paste the code below, and click the Upload button.

int LED = 13;

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

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

Step 7 of 7

Observe Results

Once uploaded, your LED should blink at 1-second intervals:

[LED ON] ── (1 Second) ──► [LED OFF] ── (1 Second) ──► (Repeat)