Arduino Uno max input current?

Development Boards Arduino
1

Hi,

What is the maximum (or for that matter, nominal) input current that the Arduino Uno board can handle, through each of its power supplies (USB, jack, Vin/GND)? It doesn’t say on the official page. The only hint it gives is that it has a 500 mA fuse for the USB connection, and the pins carry 40 mA. This seems pretty important.

I’ve verified that hooking up a 9 V battery straight to the Uno works at least short-term, I’m worried about frying it though. Do I need a current limiting resistor?

2

Most devices only draw the current they need. As long as there is enough current to run the Arduino you are good, and having more doesn’t matter.

Consider that you can plug a LED nightlight into the same wall plug that could power your refrigerator.