Build a breadboard LED circuit

Let’s build.

A low-voltage introductory activity. Never use mains electricity on a breadboard. Start with the “Your first electronic circuit” learning track.

1. 01

   Gather a breadboard, a red LED, a 330 Ω resistor, jumper wires and a regulated 5 V learning supply. Check the LED ratings.

2. 02

   With power disconnected, connect positive supply through the resistor to the LED anode. Connect the cathode to ground.

3. 03

   Check the connections and LED orientation. Ask an instructor to review your wiring if you are new to electronics.

4. 04

   Apply power briefly. If the LED stays dark or any component warms up, disconnect immediately and inspect the circuit.

5. 05

   Draw your final circuit and record your component values. Share what you learned in the Electronics community.

// iSpark Electronics: Bench LED Blinking & Polarity Verification
// Target: ESP32 NodeMCU v2 / Arduino Uno
const int LED_PIN = 2; // GPIO2 on ESP32 NodeMCU (or Pin 13 on Arduino)

void setup() {
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(115200);
  Serial.println("[iSpark] Starting breadboard LED test...");
}

void loop() {
  digitalWrite(LED_PIN, HIGH); // Supply 3.3V/5V logic high (Forward biased)
  Serial.println("LED State: ON (Current flowing through 330 ohm resistor)");
  delay(1000);

  digitalWrite(LED_PIN, LOW);  // Supply 0V ground (Cutoff)
  Serial.println("LED State: OFF");
  delay(1000);
}