5V DC

// Canonical beginner example for a 5V DC power source
// This example shows how to wire a 5V source to power the Arduino Uno.
// Note: Do not connect two power supplies to the Uno at the same time unless you know what you are doing.

void setup() {
  Serial.begin(9600);
  while (!Serial) {
    ;
  }
  Serial.println("5V DC source connected to Arduino UNO 5V and GND.");
  Serial.println("The board is powered externally through the 5V pin.");
}

void loop() {
  // No runtime control is needed for a power source example.
}