A peripheral device is a piece of hardware that can function as an input or output device that gives a computer additional functionality. They are connected to the PC via standardized interfaces. These connections can be implemented optically or via a cable or USB. The classic definition of peripheral device is “a device connected to the central processing unit”. This also includes internal hard disk drives, sound cards, graphics cards and other extensions in the PC. All the peripheral devices together are called “the peripheral”. Peripheral devices can be viewed as auxiliary devices and external extensions to a computer. Peripheral devices can be subdivided into the groups input devices, output devices and storage units. Among the devices for data entry including all traditional input devices keyboard , computer mouse (even a hyperscroll mouse) , joystick , scanner , graphics tablet , light pen , reading pen , Surface pen , touch screen , multi-touch screen , data glove and card readers for smart cards , magnetic cards , bar code ,Fingerprints , etc. There are also peripheral devices for capturing sound, photos, and videos such as microphones, digital cameras, video cameras and camcorders. Storage units are usually external hard drives, but you can even connect your laptop hard drive to a PC – which stretches the bounds of what you would classify as a peripheral! However, peripheral devices are not necessary for the computer to perform its basic functions. They can be seen as enhancements that the user needs. Unlike a computer, a peripheral device is usually unable to function independently. Peripheral devices take on various tasks and roles, or functions.
