At what voltage does a USB host supply power to the USB bus?

A.
15 volts

B.
5 volts

C.
50 volts

D.
3 volts

Explanation:

A USB host supplies power to the USB bus at 5 volts. The USB light is a device that uses power from
the bus to power small LEDs. USB lights are generally used for lighting keyboards at night. Most of
the USB devices that require more power to operate have separate power outlets.
What is USB?
Universal Serial Bus (USB) is a high speed bus standard developed by Compaq, IBM, DEC, Intel,
Microsoft, NEC, and Northern Telecom. It provides the Plug and Play capability of Windows to
external hardware devices. USB supports hot plugging, which means that a USB device can be
installed or removed while the computer is running. A single USB port can be used to connect up to
127 peripheral devices, such as CD-ROM drives, tape drives, keyboards, scanners etc. USB 1.1 has a
maximum data transfer rate of 12 Mbps, whereas USB 2.0 has a maximum data transfer rate of 480
Mbps. USB 2.0 is
fully backward compatible with USB 1.1.