This adapter allows you to connect a barrel jack connector to bare wires. One end has screw terminals and the other has a 5.5x2.1mm, center-positive male barrel jack.
This adapter allows you to connect a barrel jack connector to bare wires. One end has screw terminals and the other has a 5.5x2.1mm, center-positive female barrel jack.
Most Arduinos have 5.5x2.1 mm socket, but sometimes you'll have a power supply with 5.5x2.5 mm plug (most 'desktop' PSU have this plug) and then you can use this socket for your project.