Itc lec 4 input devices

Introduction to
Computer Applications
Lecture # 4

Objective of Lecture
 Input devices
 Types of Input Device
 Keyboard
 Pointing Devices and its types
 Scanners
 Digital camera
 Voice input devices

Input Devices
 Computer cannot understanding our
language because it understands only
machine language and it can be possible
using some devices are called input
devices
 When we work with computer we need to
enter data and instructions to the
computer using these devices
 Input devices receive data
and instruction from outside,
and send them to CPU.

Types of Input Device
 Input device is any hardware component used to enter data or
instructions
 Keyboard
 Pointing Devices and its types
 Scanner
 Digital camera

What Is Input?
 What are two types of
Input
 Data
 Unprocessed text,
numbers, images,
audio, and video
 Instructions
 Programs
 Commands
 User responses

The Keyboard
 Keyboard is the most commonly used
input devices.
 They allow data entry into a computer
system by pressing a set of keys neatly
mounted on a keyboard
 Contains some extra command keys
and function keys that affect the
operation of computer or keyboard
itself
 Keyboard can be divided into
 Typing area
 Numeric keypad
 Function keys, special keys that
issue
commands

The Keyboard
 What are alternative forms for commands?
 Many programs allow you to use key
combination, menu, or button to obtain same
result
MICROSOFT WORD KEY COMBINATION EQUIVALENTS
Key Menu |
Command Combination Command Button
Copy Shift+F2 or Edit | Copy
Ctrl+C
Open Ctrl+F12 File | Open
Paste Ctrl+V Edit | Paste

The Keyboard
 What is the insertion point?
 Blinking vertical bar that
indicates where next
character you type will
display
 Pointer changes
location and shape
as you move mouse
or other pointing
device

Pointing Devices
 A pointer represents a small symbol on the screen. It
usually appears on the screen in Graphical User
Interface (GUI) environment. A pointing device is an
input device. It is used to control the movement of the
pointer or cursor on the screen. It can also be used for:
 Sending command signals to the computer.
 Selecting items on the screen.
 Selecting commands from commands menu.
 Drawing graphs etc.

Types of Pointing Devices
The most important pointing devices are as follows:
 Mouse
 Trackball
 Pointing Stick
 Joystick
 Touch Pad
 Touch Screen
 Light Pen

Mouse
 Mouse is the most commonly used pointing input
device. It is used to control the cursor or pointer on the
screen and to give commands to the computer. It is very
easy to use. The mouse is attached with the computer
by a cable or wireless connection
 The top of mouse contains one wheel and 2 or 3 buttons.
These buttons can be clicked or double clicked to
perform different tasks.
Example: For example, an object (icon) on the screen is
selected by clicking the left button of mouse. Similarly, a
program or folder is opened by double clicking the left
button of mouse.

Trackball
 A trackball is a pointing input device. It performs
functions like a mouse but it is a stationary device. It has
move-able ball on its top. The ball is rotated or rolled
with fingers (or palm of the hand) to move the pointer on
the screen. Like mouse, a trackball also has buttons
used to send the commands to computer.
 The trackball is usually available laptop compute. It is
fixed on its keyboard. It is also available as separate
input device.

Touch Pad
 Touch Pad is a pressure-sensitive pointing device.
Touch pad is also known as track pad. It is also
stationary device like trackball but it has no moving arts.
It is a small, flat surface (or sensitive pad) over which a
user slides fingertip to move the pointer on the screen.
 Touch Pad also has one or two buttons. These buttons
are located near the pad. These buttons work like mouse
buttons. Touch Pad is normally used with laptops.
Nowadays, it is also available as separate input device.
It is fixed on separate keyboard.

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

Joystick
 Joystick is a pointing device. It consists of a vertical
handle or hand-held stick. The stick is mounted on a
base. The hand-held stick is used to control the
movement of pointer on the screen. Joystick also
contains one or two buttons. The button of the joystick is
pressed to activate certain event or action. Joystick is
basically used to play video games. It is also used in
some computer-aided design (CAD) system.

Touch screen
 A touch screen is a special video display screen. Input is
given to the computer directly by touching the screen
with user fingertip. Most touch screen computers use
sensors in the computer's screen to detect the touch of a
finger. Usually touch screen used to make selection from
a menu of choices displayed on the screen. Touch
screen is often used in ATM. Touch screen systems are
also used in restaurants, supermarkets, departmental
stores etc.

light pen
 The light pen is a hand-held pointing input device. It looks like a pen.
It is a light-sensitive input device. It is connected with the computer
by a wire. The tip of pen contains a light-sensitive element. This
device also contains a button.
 Input is given to the computer directly by touching the screen with
pen. When the pen is touched with the screen, it detects or senses a
position on display screen. The user points the object to be selected
on the display screen and then presses a button on the light pen.

Scanner
 Data scanning devices are input devices used for direct data entry
into a computer system from source documents. It converts every bit
of the scanned material into electrical pulses.
 Common scanner devices are:
 Magnetic Ink Character Recognition (MICR) reader :- used by
banks to process large volumes of cheques and drafts
 Optical Mark Reader (OMR) scanner :- scanning the answer sheet
of an objective type test in which answers are marked by darkening
a square or circle space by pencil.
 Optical Character Recognition (OCR) scanner :- used for direct
reading of any printed character
 Barcode reader :- used to read the barcodes printed on practically
every item purchased from a department store

DIGITAL CAMERA
 A computer with a vision-input device consists of digital
camera
 The camera creates an image of the object in digital form so
that It can be stored and interpreted by the computer

Voice input devices (Microphones)
 Today’s computer are capable to work as you speak
before it.
 For this type of input, you need a microphone and a
sound card.
 Microphone converts the sound into electrical signals.
These electrical signals are translated by the sound card
into digital form that computer can store and process.
sound
Electrical
signals
Digital form
Store and
process

Itc lec 4 input devices

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