1pcs 9v 1a DC Power Adapter EU 5.5mm*2.1mm Interface Power Supply 100-240V AC Adapter for Arduino UNO MEGA

FAQ:

Adapter INPUT : 100-240V ~ 50-60Hz mean that adapter can work below 100V-240V voltage normally.

Adapter OUTPUT : Two figures can be very fast to calculate the adapter wattage .For example, Voltage 12V * Current 1A = 12W (Power), this power is 12W .

Power supply Nominal voltage : it is the voltage of the open output, it is not connected to any load outside. So it can be understood as This voltage is the upper limit of the power supply output voltage.So if you want to measure the voltage, you need to measure the voltage at no load.

Nominal current of the power supply: The current is different depending on the load conditions. But the upper limit for the maximum adapter current. For example, The 12V 2A adapter is connected to a 12V 2A load, the current value is 2A. The 12V 2A adapter is connected to a 12V 1A load, The current value is 1A. So when you measur current, You should string the appropriate load.