Chapter No – 1
Input and output devices
Input Device Definition: A piece of equipment/hardware which helps us enter data into
a computer is called an input device. For example keyboard, mouse, etc.
Output Device Definition: A piece of equipment/hardware which gives out the result of
the entered input, once it is processed (i.e. converts data from machine language to a
human-understandable language), is called an output device. For example printer,
monitor, etc.
List of Input Devices
Given below is the list of the most common input devices along with brief information
about each of them.
1. Keyboard
A simple device comprising keys and each key denotes either an alphabet, number or
number commands which can be given to a computer for various actions to be performed
It has a modified version of typewriter keys
The keyboard is an essential input device and computer and laptops both use keyboards to
give commands to the computer
2. Mouse
It is also known as a pointing device
Using mouse we can directly click on the various icons present on the system and open up
various files and programs
A mouse comprises 3 buttons on the top and one trackball at the bottom which helps in
selecting and moving the mouse around, respectively
In case of laptops, the touchpad is given as a replacement of the mouse which helps in the
movement of the mouse pointer
3. Joy Stick
It is a device which comprises a stick which is attached at an angle to the base so that it can
be moved and controlled
Mostly used to control the movement in video games
Apart from a computer system, a joystick is also used in the cockpit of an aeroplane,
wheelchairs, cranes, trucks, etc. to operate them well
4. Light Pen
It is a wand-like looking device which can directly be moved over the device’s screen
It is light-sensitive
Used in conjunction with computer’s cathode ray tube
5. Microphone
Using a microphone, sound can be stored in a device in its digital form
It converts sound into an electrical signal
To record or reproduce a sound created using a microphone, it needs to be connected with
an amplifier
6. Scanner
This device can scan images or text and convert it into a digital signal
When we place any piece of a document on a scanner, it converts it into a digital signal and
displays it on the computer screen
7. Barcode Reader
It is a kind of an optical scanner
It can read bar codes
A source of light is passed through a bar code, and its aspects and details are displayed on
the screen
