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Chapter wise slides of Bs Comp Sci, Study notes of Computer Science

Punjabi University Computer Science

Chapterwise slides of Bs Comp Sci

Typology: Study notes

2018/2019

Uploaded on 12/24/2021

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This book is compiled for all

BS/ADP disciplines. First 10

chapters (from page 1 to 205)

included in this book are

related to computer concepts

and other chapters are related

to the Windows 7, MS office

2010 (Word, Excel, PowerPoint,

Access), and InPage 2000 with

practical.

Partial preview of the text

Download Chapter wise slides of Bs Comp Sci and more Study notes Computer Science in PDF only on Docsity!

This book is compiled for all

BS/ADP disciplines. First 10

chapters (from page 1 to 205)

included in this book are

related to computer concepts

and other chapters are related

to the Windows 7, MS office

2010 (Word, Excel, PowerPoint,

Access), and InPage 2000 with

practical.

Chapter 3 Input and Output Devices

INTRODUCTION TO COMPUTER

Input & Input Devices

Chapter 3 - Input and Output Devices

Input & Input Devices

Anything given to the computer is called input
Data and instructions are given to the computer as input
Input into the computer can be entered:
- through a keyboard (by typing characters)
- by selecting commands (icons) on the screen and then clicking with a mouse
- by pressing a finger on a touch screen
- by speaking into a microphone
- by sending the image through a digital camera
- by scanning data printed on paper through scanner etc.

Keyboard

Keyboard is the most commonly used input device
It is mostly used to enter text and numeric type data into the computer
Buttons on the keyboard are called keys
Keyboard contains keys for all alphabetic characters, numeric digits, and special characters
It also contains some special keys known as function keys
A standard keyboard contains more than 100 - keys → QWERTY keyboard
- This is because first six leftmost keys on top row of alphabets are Q, W, E, R, T, and Y

Keyboard

A keyboard is connected to serial or USB port on system unit
Some keyboards do not require cable to connect with computer
These keyboards enter data into computer through wireless technology such as radio waves (Bluetooth) or infrared light waves (IrDA)
These types of keyboards are known as Cordless or Wireless keyboards
Parts of Keyboard
- Function keys
- Main keyboard
- Numeric keys
- Additional keys

Keyboard

Numeric keys
- This part of keyboard consists of numeric keys and arithmetic operator keys
- These keys are usually located on the right of the keyboard
- These keys are similar to calculator keys
- This part of keyboard also has an extra Enter key and Num Lock key
- Num Lock key is used to activate or de-activate numeric keypad
- It is a toggle key
Additional Keyboard
- Keyboards also have some additional keys
- Most of these keys are used to move cursor inside the document
  - Arrow keys, Insert, Delete, Home, End, PgUp, PgDn, Print Screen, Scroll Lock, Pause, Windows

Pointing Devices

A pointing device is an input device that is used to control a pointer (cursor) on the screen and to give commands to the computer
A pointer represents a small symbol on the screen
It usually appears on the screen in the Graphical User Interface (GUI)
- For example, an arrow appears on the screen in the Windows environment
Location of the pointer on screen changes as a user moves pointing device
Pointing device can be used to select text, graphics, or other objects and to open a file/folder or run a program
Similarly, we can perform many other functions very easily and quickly using a pointing device - For example, engineers use pointing devices to draw graphs or maps
Examples → mouse, joystick, trackball, trackpad, light pen, etc.

Pointing Devices Mouse (Types of Mouse)

Mechanical Mouse
- A mechanical mouse has a rubber or metal ball inside it and an electronic circuit containing sensors
- Ball rotates as mouse is rolled over a flat surface
- Movement of pointer depends on rotation of ball
- Nowadays, this type of mouse is rarely used
Optical Mouse
- No ball inside it. It uses a device that emits and senses light to detect the movement of the mouse
- Some optical mouse devices use optical sensors, and other use laser to detect the mouse movement
- Nowadays, the optical mouse is commonly used in personal computers (PCs)
Wireless or Cordless Mouse
- Not directly connected with computer
- It uses wireless technology, such as radio waves (Bluetooth) or infrared light waves (IrDA)
- It enters input signals into computer in a similar way as a cordless keyboard
Air Mouse
- Air mouse is similar to a remote control
- It is a motion-sensing mouse
- It is used in presentations for running slide shows, controlling media, and other objects
- For example, raising mouse up might increase volume of media player
- Air mouse works in air by detecting the direction of hand motion

Pointing Devices Trackball

It performs functions like a mouse but it is a stationary device
It has a moveable ball on its top
The ball is rotated or rolled with fingers (or the palm of the hand) to control the movement of a pointer on the screen
Like a mouse, a trackball also has buttons used to send commands to computer
However, a trackball has additional buttons whose functions vary depending upon software
Trackball is usually available with a laptop computer
It is fixed on its keyboard
A trackball is also available as a separate input device
Some cordless trackballs are also available
These are not directly connected to computer with a wire

Pointing Devices Pointing Stick

A pointing stick is a pressure-sensitive pointing device
It looks like a pencil eraser
It exists between the keys of keyboard
It is used to control the movement of a pointer on the screen
The pointer on the screen moves in the direction in which the pointing stick is pushed
A pointing stick input device is normally used with laptops

Touch Screen

A touch screen is a touch-sensitive display device
Input is given to the computer directly by touching the screen with the user’s fingertip or stylus
Usually, touch screen is used to make a selection from a menu of choices displayed on the screen
Touch screens are commonly used in mobile computers and mobile devices such as smartphones and tablets
Some models of desktop computers and laptops also have touch screens
Example → Automated Teller Machines (ATM) interface
Today, most of the touch screens are multi-touch
- Multi Touch → Touch screens that can recognize multiple points of contact at the same time
- It means that a multi-touch screen can take input from two or more fingers at the same time
- For example, a user can use his/her two or more fingers to enlarge or rotate an image on the screen

Joystick

Joystick is a vertical handheld lever mounted on a base
Lever can be moved in different directions to control the movement of object (or pointer) on the screen
Lever also includes two or more buttons → triggers
A button is pressed to activate a certain event or action
A joystick is basically used to play video games
It is also used in some computer-aided design (CAD) systems
A joystick can be attached to a personal computer or game console via a cable

Digital Camera

Captures (or takes) pictures and stores them in digital form
Captured pictures are stored in its memory
The number of pictures that a digital camera can store depends upon its memory size
Most digital cameras store pictures on flash memory or flash memory card or memory stick etc.
Usually, flash memory cards are used inside digital cameras to store pictures
A digital camera also has an LCD for viewing the pictures
Many digital cameras can also record moving videos with sound
Today most of the smartphones and other mobile devices have built-in cameras
Usually, pictures/videos are downloaded from a digital camera to the computer

Chapter wise slides of Bs Comp Sci, Study notes of Computer Science

Related documents

Partial preview of the text

Download Chapter wise slides of Bs Comp Sci and more Study notes Computer Science in PDF only on Docsity!

This book is compiled for all

BS/ADP disciplines. First 10

chapters (from page 1 to 205)

included in this book are

related to computer concepts

and other chapters are related

to the Windows 7, MS office

2010 (Word, Excel, PowerPoint,

Access), and InPage 2000 with

practical.

Chapter 3

Input and Output Devices

Input & Input Devices

+Making photos is inexpensive and fast because it does not require any film processing

+The pictures taken by the digital camera can directly be inserted into the documents