In this Lesson
A power supply is a critical part when it comes to microcontrollers. The power supply refers to the source of electrical power. First, we will look at using one power supply for your Arduino board, and then we look at using multiple power supplies. The most common operating voltages for Arduino are 5V and 3.3V. 5V to 12V power supplies are standard.
You can supply an Arduino Board using the DC barrel jack or use the VIN and GND pin. If you connect power to the DC barrel jack, it will reach a regulator that is on board. In case you want to connect your power source to the VIN / GND pin of the board, you will need to add a voltage regulator.