Peripheral devices of Computer

Peripheral devices of Computer

PERIPHERAL DEVICES

Peripheral devices are connected to the computer externally.

These devices are used for performing some specific functions.

Peripheral devices are as follows:

1. Input Devices

2. Output Devices

3. Other Peripherals

INPUT DEVICES

Input devices accept data and instructions from the user.

Following are the examples of various input devices, which are

connected to the computer for this purpose.

 Keyboard

 Mouse

 Light Pen

 Optical/magnetic Scanner

 Touch Screen

 Microphone for voice as input

 Track Ball

 Monitor

 Disk drives 

Keyboard

A keyboard  is the most common input

device. Several kinds of keyboards are available, but they

resemble each other with

minor variations. The

keyboard in most common

use is the QWERTY board.

Generally standard

keyboard has 104 keys. In

these keyboards, the cursor

control keys are duplicated

to allow easier use of the

numeric pad.

Mouse

A mouse is an electro-mechanical, hand-held

It is used as a pointer. It can perform functions

like selecting menu commands, moving icons, resizing windows,

starting programs, and choosing options.

The most common mouse uses an internal, magnetically coated

ball, to detect the movement of the mouse across a flat surface,

usually a desktop. Now a days Optical or laser mouse is used to

detect the movement. All windows based applications today are

designed to work with a mouse. A mouse is used to replace hard

-to-remember key combinations with easier "Point and Click"

actions. However, it cannot substitute all keyboard operations.

It can be alternative for commands based operations.

Light pen

An input device that utilizes a light-sensitive

detector to select objects on a display screen.

A light pen is similar to a mouse

, except that with a light pen you can

move the pointer and select objects on the

display screen by directly pointing to the

objects with the pen.

Optical Scanner

These devices are used for automatic data collection. The

devices of this category completely eliminate manual input of

data. For example, the bar-code reader is actually just a special

type of image scanner. An image scanner translates printed

 Touch Screen

Touch panel displays and pads are now being offered as

alternatives to keyboard. Here the input can be given through the

computer screen, that accepts the input through monitor; users

touch electronic buttons displayed on the screen or they may use

light pen.

Microphone

Microphone is an input device, which takes voice as input. The

voice communication is more error-prone than information

through keyboard. There are two types of microphones available

1. Desktop Microphone

2. Hand held Microphone

Track Ball

Trackball, a pointing device, is a mouse

lying on its back. To move the pointer, you rotate the ball

with your thumb, your fingers, or the

palm of your hand. There are usually one

to three buttons next to the ball, which

you use just like mouse buttons.

The advantage of trackballs over mouse is that the trackball is

stationary so it does not require much space to use it. In addition,

you can place a trackball on any type of surface, including your

lap. For both these reasons, trackballs are popular pointing

devices for portable computers. 

OUTPUT DEVICES

Output devices return processed data that is information, back

to the user. Some of the commonly used output devices are:

1. Monitor (Visual Display Unit)

2. Printers

3. Plotter

4. Speakers

Out of all the output devices,

Monitor is perhaps the most

important output device

because people interact with

this device most intensively

than others. Computer

information is displayed,

visually with a video adapter card and monitor. Information

processed within the CPU, that needs to be visually displayed,

is sent to video adapter. The video adapter converts information

from the format used, in the same manner as a television displays

information sent to it by a cable service.

Monitor

Two basic types of monitors are used with microcomputers,

which are as follows:

1. CRT

2. LCD

3. LED

Printer

After a document is created on the computer, it can be sent to a

printer for a hard copy (printout). Some printers offer special

features such as colored and large page formats. Some of the

most commonly used printers are

1. Laser Printer

2. Ink Jet Printer

3. Dot Matrix Printer

4. Line Printer