Duemilanove power source auto-select, both?

What happen if I connect a 12V DC Adaptor to the DC IN connector in my duemilanove and then plug it to the USB?

I am asking this because the duemilanove does not have the "power" switch to choose the source.

Thanks

Sorry but the duemilanove does have automatic switching. Are you sure it is a duemilanove you have?

The boards without automatic switching has a link to swap over so you can't power from two sources at the same time.

If both USB and External power are present the automatic power selection logic will select the external power for the board and route this to the internal +5vdc regulator to power the components on the board. When only USB power is avalible then the +5vdc regulated voltage from the PCs USB connector will power the board components, bypassing the internal +5vdc regulator.

Lefty

Cool, thanks retrolefty