using an external power supply

Development Tools IDE 1.x
1

Hi,
my Arduino Mega 1280 project works fine, when i connect the usb cable, now i tried putting in a 8,5V wall wart (center positiv) into the power jack and some of the leds are on but the programm doesnt seem to run...

Should it work, or do i have to add an extra 5V regulator which is connected to the 5V pin?

Furthermore, can I connect the external Psu when the board is connected via USB without damaging anything?

  • FLo
2

What kind of power supply is it? Have you measured its output? Is it switch-mode or linear or non-regulated?

3

it is a simple 9V dc wall wart. i measured about 8,5V between the center pin and the outer ring of the jack.

Should this work just like this?

4

I just used an Wall wart with about 13V
my device functioned but the power regulator left to the power input jack gets hot extremly fast.

what is wrong?