The Arduino's power supply is in the lower left hand side of the PCB. From The Components of an Arduino Uno PCB -… | Instagram
Photo of the power supply circuit, Arduino Nano Cards ATmega328, and... | Download Scientific Diagram
![Arduino Uno External Power Supply - Arduino - Electronic Component and Engineering Solution Forum - TechForum │ Digi-Key Arduino Uno External Power Supply - Arduino - Electronic Component and Engineering Solution Forum - TechForum │ Digi-Key](https://global.discourse-cdn.com/digikey/original/2X/0/00013e06df40492d2e56debbdcd28ab26bcbf0e9.jpg)
Arduino Uno External Power Supply - Arduino - Electronic Component and Engineering Solution Forum - TechForum │ Digi-Key
![Volteq HY3030EP Programmable DC Power Supply with Built-in Arduino Control | Ideal for Testing and Charging Volteq HY3030EP Programmable DC Power Supply with Built-in Arduino Control | Ideal for Testing and Charging](https://volteq.com/images/source/HY3030EP.jpg)