I have Apacer AudioSteno va210 256 mp3 player
I would like to know what will happen if i'll connect power for it from nokia car charger. i think there is 4V voltage and about 350mA. That player uses 1x1.5V battery but i think that USB port outputs higher voltage so it shouldn't be damaged by 4V.
So i would like to know what is the possibility to damage my mp3 player? what will happen if i connect wires in bad polarity?
And i am wondering what highest voltage can these usb keys take? And what is the exact USB port voltage?