2. Input devices
“The hardware components used to enter data, programs, commands, and users
response into a computer are called input devices.”
If the user interact with the computer, he needs an input devices.
Example:
Keyboard
Mouse
Digital Camera
Webcam
Scanner
3. Keyboard
“Keyboard is an input device that has certain several buttons called keyboard keys
and user press these keys to enter data or instruction into computer.”
We can enter text, number, symbol and special characters by using keyboard
Keyboard is connected by serial and USB port with computer system
4. Process of Keyboard
The computer processor scans the keyboard hundreds of times per second to see
when a key has pressed.
When a key pressed, a digital code is sent to central processing unit (CPU). This
digital code is translated ASCII Code (American Standard Code of information
interchange).
Press “A” key
Produce Binary code 01000001that is called back end process
Monitor show the letter “A”
5. Keys
The buttons of the keyboard are called keys. Keys are arranged in specific order.
The keyboards are available in many different arrangements and layouts.
For example:
I. Qwerty layout
II. Dvorak layout
6. Qwerty Layout
Most type writer and computer keyboards follow the scheme QWERTY. The
alphabetic keys are arranged so that the upper left row of letters begins
With the six letters Q W E R T Y.
7. Dvorak layout
Dvorak layout was designed in 1980s by August Dvorak. In Dvorak layout middle
rows of keys includes the most common letters. The letters are arranged in such
way it can be typed easily and quickly. But it is not popular layout of keyboards for
fast typing.
8. Keys of keyboard
Alphabetic Keys: A -- Z
Numerical Keys: 0 -- 9
Symbols Keys: !, @, #, $, %, &, *,
Function Keys: F1--- F12
Multimedia Keys: down, forward, Rewind, next,
Special Purpose Keys: Esc, Alt, Ctrl, Backspace, Enter
9. Types of Keyboard
Traditional keyboards: Full sized, Inflexible
Flexible keyboards: easy carrying and flexible as mobile keyboards
Ergonomic keyboards: comfort for user hands and wrist
Wireless Keyboards: transfer input through Bluetooth
10. Advantage of Keyboard
Reliable
Skilled Typist
Type as you want to write
Data enter quickly
11. Disadvantage of Keyboard
To make typing mistakes
Time consuming
Difficult for the people that are unable to use it
Harmful for wrist
12. Mouse
Mouse is an input device that fits under the palm of a hand and controls
movement of pointer or cursor.
The mouse is a palm sized device with the ball rolling at the bottom. The mouse is
usually connected with computer by cable.
When you move the mouse over a smooth surface, the balls rolls and signals is
generated which moves the pointer on the display screen accordingly.
You can draw, select, lines or other graphics.
13. Types of Mouse
Mechanical mouse: Metal or rubber ball at its bottom
Optical mouse: Light emitting laser to detect movement
Wireless mouse: Work via radio frequencies, also called cordless mouse
14. Advantage of Mouse
Ideal for use with desktop computer
Help for drawing
Attach with laptop
Light weight
Disadvantage of MOUSE
Need a flat space
Jammed due to dust
15. Touch pad
A touch pad is a device for pointing on a computer display screen.
Alternative to mouse
Touch pad also has two buttons as like mouse
ADVANTAGE
Convenient
Easily useful as compare with mouse
16. Touch Screen
A touch screen is a computer display screen that is also an input device. The screen
are sensitive to pressure; a user interact with the computer by touching pictures or
words on the screen.
17. Advantage of Touch screen
Easy to use
Flexible
Disadvantage of Touch screen
Not suitable for inputting large amounts of data
Not very accurate
Expensive than alternatives such as mouse
