12V DC power supply

// Canonical example for a 12V DC source component
// Note: This is a passive power source. It is not controlled by the Arduino,
// so the example focuses on the safety connection of the negative terminal to GND.

void setup() {
  Serial.begin(9600);
  while (!Serial) {
    ;
  }

  Serial.println("12V DC source example");
  Serial.println("Connect the negative terminal of the 12V supply to Arduino GND.");
  Serial.println("The positive terminal is intentionally left unconnected in this canonical example.");
}

void loop() {
  // No runtime action: this component is a DC power source.
}