Arduino Due and Vin, 3.3V and 5V power inputs I just want to confirm something before I wire up my first ever Arduino project and fry all the stuff I just spent money on.

It is my understanding that the Vin power input will tolerate a 9V battery and use voltage regulators to pare it down to either 3.3V or 5V (as different parts of the board require). So it is then my assumption that if I have a 9V battery running to Vin, that I could then connect a power wire to the 3.3V connector, and reliably get a 3.3V signal (and ditto for 5V), yes?

Or, is it that they are input jacks expecting either 3.3V or 5V signals? I guess I'm confused over this:


Will Vin then power the 3.3V and 5V inputs, giving me access to voltage at that level; or
Do I have to choose between 3.3V, 5V or Vin, and only use one of those to power my board (with the appropriate voltage level)
DC Jack is connected, through a diode, to Vin.

Vin is stepped down to 5V on-board.

5V is stepped down to 3V3 on board.

Thus you can do any one of the following numbered items.


Connect a 7-12V supply to the DC Jack; thus:


use Vin as a supply @ DC - 0.7V for off-board peripherals, and
use 5V as a supply for off-board peripherals, and
use 3V3 as a supply for off-board peripherals.

Connect a 6-12V supply to Vin; thus:


use 5V as a supply for off-board peripherals, and
use 3V3 as a supply for off-board peripherals.

Connect 5V supply to the 5V; thus:


use 3V3 as a supply for off-board peripherals.



The above is only guaranteed for boards that follow the reference schematic, as plenty of clone/compatible boards do. If you buy a cheap Chinarduino and something doesn't work, or the thing breaks, after following anything above then that's your tough luck.