A power adapter that generates the 5 volt DC standard required by USB. The amperage varies, typically from .07A to 2.4A. 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
USB chargers connect to the cable via a Type A USB socket. Geared to the device, the cable has a smaller plug at the other end (see Mini USB
, Micro USB
and USB Type C
Open up a typical charger and you find a couple of chips and several discrete components.
Chargers Are Everywhere
Passengers can charge their devices by plugging them into this USB port on the back of the seat in front of them.