USB Flash Drive

A USB flash drive, sometimes also a USB key, is a miniature data medium that is intended for data transfer between computers. It usually takes the form of a key chain or a pendant and is equipped with a flash memory, which allows data to be stored even when the power is disconnected. The data is uploaded to the memory via the USB bus, hence the name. Although sometimes called a disk, there are no moving parts in the device.

USB flash drives are the successor to previously used floppy disks and optical disks. Their advantage is smaller size and low weight - most weigh less than 30 grams and are more durable and reliable. They are immune to magnetic fields (unlike floppy disks) and do not mind surface scratches (unlike CDs).

USB flash drives use the USB Mass Storage standard for data storage, which is supported by all commonly used operating systems, as well as game consoles, DVD players, and portable devices such as smartphones, tablets, and computers.

Flash drives consist of a small printed circuit board that has integrated circuits that are protected by a plastic, metal, or rubberized case. They also contain a control unit for memory communication with the PC, a memory chip for data storage and a crystal that produces the main clock signal (originally 12 MHz). Additional devices can also be a technical connector for production testing or code recording to the control unit, an LED diode indicating whether data is being read or written, and a lock or switch enabling write blocking.