I'm not sure I understand your question. Assuming that is a Uno on the bottom, it has (typically anyway) a 2.1mm barrel plug in which it wants to see about 9V to power the on board 5V and 3.3 volt regulators. The device on the top looks to have either a 1.3mm or 1.7mm barrel connector (from the apparent size I'd guess its 1,3mm but screens are deceiving :slight_smile) . Where does the 5 volts enter the picture? Does the device on the top want 5 Volts in to the power jack?
The capacity of the power supply is unrelated to the size of the output jack, to find its capacity you would need to either find a plate on it that lists its input and output voltages and currents or find a part number and google for a data sheet.
Peter Van Epp