USB charger - Computer Definition
A power adapter that generates the 5 volt DC standard required by USB. The charger plugs into an AC outlet, and a USB cable plugs into the charger. USB ports on computers have an upper limit of 500 milliamps; however, USB chargers that come with cellphones and other devices handle one or more amps. The devices sense when they are connected to a computer versus the charger and regulate their current draw. See power adapter.