I'm sorry for this question, but a quick search didn't help me get the info I want. So, I found in an old drawer an A20-Olinuxino-Micro board, but it seems that I've misplaced the power adapter it once had. In the documentation it's written that the board needs a "6-16V input power supply". My question is what does this mean? Will any power supply that provides a voltage between 6V and 16V work? I found a 9V adapter which can give enough ampers, would it work? Thanks and sorry for the stupid question.
The various Olimex docs
e.g. at https://www.olimex.com/wiki/A20-OLinuXino-MICRO#A20-OLinuXino_Board_User_Manual
show 6-16V DC (low noise) so your 9V is likely OK. It's not going to cause damage even if a bit (electrically) noisy. Worst case maybe reboots.
John
Yes, 9V DC is completely fine. Make sure it can provide at least 0.5A at 9V (4.5W) but preferable if it can provide 1A at 9V (9W). Make sure its jacks fits on-boards jack, you can learn about the power jack here:
https://www.olimex.com/wiki/PWRJACK