Only getting 3.3 volts

Development Boards Arduino
1

Hi, when I plug in a 5v power brick lead to the power socket on the Uno, I only get 3.3v. If I plug in the 9v wall wart I get 5v.

If I use USB cable with the power brick to the USB on the board, I get 5v.

Do I have a faulty Uno, or is there a jumper to tell it to pass the 5v straight through the power socket?

2

I suggest reading the very widely available “getting started” material.

The Uno is functioning as specified. The power socket input voltages must be between 7 and 12 V.

3

Thanks, that makes sense. I am old (76) and don’t have a lot of time left for reading lengthy dissertations, asking is always faster. :slight_smile: