What would be needed to power a USB device through a 120V outlet?

i have a set of speakers that I have to have plugged into the USB and computer/mp3 player and i want to make something so that i can run it from an outlet(120V, standard American)

sound918 years ago
I'm going to assume you mean 120V. In order to do this, there are a few options. The first and easiest would be to find a wall transformer that already has an output of 5V and at minimum 100 miliamps. The other way which is usually more readily available would be to find a transformer with the output anywhere between 5 and 35 volts. Then, put it through a 7805 voltage regulator in order to get a constant output of 5V. An easy way to get 5V transformers is old cell phone chargers.
cd41 (author)  sound918 years ago
Thanks, don't know why I put Watts must have been having an off day. thanks
frollard8 years ago
Exactly as sound91 says - they are really cheap, especially if you do the 'order from china' approach :D

http://www.dealextreme.com/details.dx/sku.37 5 dollars with free shipping.
outputs 600ma at 5v