Computer Hardware Peripherals

A computer peripheral is any external device that provides input and output for the computer. For example, a keyboard and mouse are input peripherals, while a monitor and printer are output peripherals.

There are many different peripheral devices, but they fall into three general categories:

    a)    Input devices, such as a mouse and a keyboard.
    b)    Output devices, such as a monitor and a printer.
    c)    Storage devices, such as a hard drive or flash drive.

Some devices fall into more than one category. Consider a CD-ROM drive, hard disk you can use it to read data or music (input), and you can use it to write data to a CD (output).

Peripheral devices can be external or internal. For example, a printer is an external device that you connect using a cable, while an optic disk drive is typically located inside the computer case. Peripheral devices can be connected internally as well as externally. Some of the peripheral devices are:

Some common input devices include:

a)    Keyboard  

A computer keyboard is a typewriter-style device which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches.

b)    Mouse 

A computer mouse is a hand-held pointing device that detects two-dimensional motion relative to a surface. This motion is typically translated into the motion of a pointer on a display, which allows a smooth control of the graphical user interface.

c)    Touchscreen 

A touchscreen is an input device and normally layered on the top of an electronic visual display of an information processing system. A user can give input or control the information processing system through simple or multi-touch gestures by touching the screen with a special stylus or one or more fingers.

d)    Joystick 

A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling.

e)    MIDI keyboard 

A MIDI keyboard is typically a piano-style electronic musical keyboard, often with other buttons, wheels and sliders, used for sending MIDI signals or to other musical devices or computers connected and operating on the same MIDI protocol

f)    Scanner 

 A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color.

g)    Digital camera

A digital camera or digicam is a camera that captures photographs in digital memory. Most cameras produced today are digital, and while there are still dedicated digital cameras, many more are now incorporated into devices ranging from mobile devices to vehicles.

h)    Microphone

A microphone, colloquially nicknamed mic is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, radio and television broadcasting, and in computers for recording voice, speech recognition etc.
                

                    Some common output devices include:

a)    Monitor

A computer monitor is an output device which displays information in pictorial form. A monitor usually comprises the display device, circuitry, casing, and power supply.

b)    Projector 

A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers.

c)    Display Device

 A display device is an output device for presentation of information in visual. When the input information that is supplied has an electrical signal, the display is called an electronic display.

d)    Printer

A printer is a peripheral device which makes a persistent human-readable representation of graphics or text on paper.

e)    Plotter

The plotter is a computer printer for printing vector graphics.  A plotter gives a hard copy of the output. It draws pictures on a paper using a pen. Plotters are used to print designs of ships and machines, plans for buildings and so on.

f)    Speakers 

Computer speakers, or multimedia speakers, are speakers sold for use with computers, although usually capable of other audio uses, e.g. for an MP3 player. Most such speakers have an internal amplifier and consequently require a power source.

There are also devices that function as both input and output devices, such as:

a)    External hard drives

 An external hard drive is a portable storage device that can be attached to a computer through a USB or wireless. External hard drives typically have high storage capacities and are often used to back up computers or serve as a network drive.

b)    Media card readers 

A memory card reader is a device for accessing the data on a memory card such as a Compact Flash (CF), Secure Digital (SD) or Multimedia Card (MIC). Most card readers also offer write capability, and together with the card, this can function as a pen drive.

c)    Digital camcorders 

A digital camcorder (camera recorder) is a portable electronic recording device capable of recording live-motion video and audio for later playback.