The Specs of a USB Power Adapter

 

USB is the computer standard for accessoriesTastatur und USB / Keyboard and USB image by Nazar Chabara from Fotolia.com The USB (Universal Serial Bus) hardware is the standard specification for plug-in accessories in the computer age. First created in 1994, the USB hardware has replaced most other ports on a computer. A typical USB port can be found on any system and has many uses

Voltage and CurrentThe voltage on a powered USB device varies from 4.75 volts to 5.25 volts. The maximum current for a USB 2.0 is rated 500 milliamperes when the data port is in use. It is up to 1500 milliamperes when used exclusively as a power source.PinsIn the USB connectors, Pin 1 is the positive source and Pin 4 is ground. Grounding helps to protect against electrical shock.USB 3.0The specifications for USB-powered adapters are changing. The USB 3.0 specifications have been adopted and USB 3.0 devices are starting to roll out. However USB 2.0 are still viable and in wide use. References USB as a power source ResourcesUSB 2.0 and 3.0 specifications