Can I use the Arduino Uno's 3.3v pin while powered by a 9 volt battery? I have an Arduino Uno. It has a 3.3v pin that I would like to use to power another module that requires 3.3v, and nothing more. If I power my Arduino Uno with a 9 volt battery, will this pin output 3.3v, or will it give more than that?
The 3.3v is regulated and will always output 3.3v if the device is powered on.