Hello! I have a tiny USB fiber optic Xmas tree that was given to me as a gift and it can only be used when plugged into a USB port when the computer is on. Then the tree lights up, the colors change, and all that. I would like to use this device when the computer is not on, thereby plugging it into a wall outlet. It is a very small simple little fiber optic tree 5V, and I'd rather not burn the little thing to pieces by purchasing the wrong adapter. Some adapters are for charging only, aren't they? I'm not really charging this device just letting it run. Any advice? Thank you in advance.