If you need to connect a battery pack or wired power supply to a board that has a DC jack – this adapter will come in very handy! There is a 2.1mm DC plug on one end, and a screw terminal block on the other. The terminals are labeled with positive/negative assuming a positive-tip configuration (which is the most common)
Arduino power jack.
Microcontroller trainer power jack.
Bread Board power supply jack.
CCT camera power connector.