1. Objectives

Input

The  objective  of  this  topic  is  to  provide  answers  to  the  following questions:

x     What is a keyboard?

x     What are different keys on keyboard?

x     What is their functionality?

2. Keyboard

It is an input device to give computer some input. It is like pen in writing. It is called keyboard because it is comprised of a board with keys installed. Every key send unique information to computer.

3. Keyboard types

There are different types of keyboards. Standard keyboard is the most commonly used keyboard. Key arrangement can be different for these keyboards. Some may have special keys for other tasks than just typing. These special keyboards are usually used for multimedia purposes like video editing, sound design etc.

4. Basic Keyboard keys

There are usually 104 keys on standard keyboard. Pressing the key once and releasing it is called a key stroke.

Character keys

These are used  to enter alphabetic characters. These  characters become  uppercase  when pressed with shift key or caps lock is on.

Numeric keys

There are 10 numbers or numeric keys (1, 2, 3 to 9 and 0) on standard keyboards. These are  used  in  the  same  fashion  as  typewriters’  keyboard  to  enter  numbers.  These  become symbols or punctuation marks when pressed with the shift key.

For example

1- Shift + 8 will print *

2- Shift + 4 will print $

Special keys

Shift, Alt and Control(ctrl) keys are special keys and when pressed with other keys, perform special operations. For example ctrl+c will copy the selected file or text, shift+ character key will print that character in capital.

Escape keys

It is used to escape/exit from certain type of applications.

Function keys

F1, F2, …. F12 are called function keys. These are used for different purposes. For example

F5 is used to refresh the web page in internet browser. F1 will open help window.

Arrow keys

There are four keys(arrow Keys) for cursor navigation. Left arrow key, Right arrow key

Up arrow key, Down arrow key

Numeric key pad

On the right side, a separate area is reserved for numeric keys, mathematical operational keys(+, – , * , /) , enter, dot and Num Lock key.

Space Bar

It is horizontal wide key, in the lower most row. It generates space between two characters.

Punctuation keys

These are keys to enter punctuation and are located on the right side of alphabet keys.

Enter key

Enter or return key cause cursor to go to next line, form or window to perform its default function.

Application key

It launches the menu with the keyboard rather than the usual right mouse button.

Toggle keys

Caps lock, Num lock and Scroll lock keys are toggle keys. At the top right corner, there are three small lights to show the status of these locks. When pressed one, corresponding light is turned on.

The keys on numeric key pad act as numbers and dot. When this key is pressed again and the corresponding num lock key light is switched off, the key act as arrow keys, home key, pg up, pg down and end keys.

Characters become capital when the caps lock is on.

Scroll key modifies the functionality of arrow keys. When the scroll lock is on, the arrows keys would scroll the window instead of moving the cursor.

Print screen key

It is the key which is used to save (capture) all the contents of the screen in a temporary area.

Insert key

Key use to insert or overwrite character(s) within a word is called insert key. The key acts as toggle key. If it is in the insert state than any character pressed while the cursor is placed within a word gets inserted. If the key is pressed and it is in the overwrite state than any char pressed while the cursor is placed with get overwritten.

Home key / End key

It is used to go to start (home key) or end (end key) of the document.

Page up key / Page down key

It is used to go to previous (page up key) or next (page down key) page.

Delete key

The key used to delete characters.

Backspace key

The key used to delete the preceding characters.

Special keys

Alt, Ctrl and shift keys are non-typing keys. They don’t print anything when pressed. These when pressed with other keys, modify the usual operation of that key.

For example Alt + F4 close the active window.

Tab key

Tab key is a typing key and used to put more than one space within characters or words.

5. Summary

In this topic we have learnt:

x     What is keyboard? What is its use?

x     Keyboard types

x     Standard keyboard keys

x    Character  keys,  Numeric  keys,  Bracket  keys,  Punctuation  keys,  Backspace  key, Delete key, Tab key, Caps lock key, Num lock key, Scroll lock key, Insert key, Page up/down keys, Functional keys, Special keys

6. Exercise

Practice the usage of character keys placed on the keyboard by writing

A quick brown fox jumps over a lazy dog

Write the names and numbers of all the functional keys on your keyboard. State the difference between typing and non-typing keys.

1. Objectives

Input Devices

The objective of this topic is to provide the answers to the following question:

x     What is a computer mouse?

x     What are its different forms?

x     Some other pointing devices than mouse x     Input devices for image, sound, and video

2. Pointing devices

Devices used to point things at the computer screen are called pointing devices. For example mouse, track pad, etc

Mouse

Mouse is a pointing device that works by detecting motion relative to its supporting surface. Furthermore:

There are many types of computer mouse available in the market. They  usually  have  different  shapes  or  buttons,  but  they  work almost in the same fashion.

Mouse Buttons

There are two buttons on standard mouse

1- Right mouse button                     2- Left mouse button

Mouse Pad is a surface used to sense the mouse motion.

Mouse Pointer/Arrow/Cursor shows the position and motion of mouse on screen.

Track Pad

Track pad (also known as touchpad) is a pointing device consisting of a sensitive surface that translates the motion of a user’s finger to a relative position on screen. The trackpad has no moving parts.

Trackball

The trackball is a ball inserted in a small external box near the keyboard. The ball is rolled with the fingers to move the mouse cursor. Some people like to think of the trackball as an upside- down mouse with a bigger ball at the bottom.

Trackpoint

Trackpoints are usually positioned in or near a laptop’s keyboard. They function like miniature

joysticks but are operated with the tip of the finger.

Joystick

The joystick is a vertical stick that moves the mouse cursor in the direction the stick is pushed. Joysticks are commonly used in video arcade games.

3. Other input devices

Microphone

Microphone is used to input the sound to computer. It is used in motion pictures, radio and television broadcasting etc.

Scanner

Scanner is a device that scans images, papers etc to store them in computer for later use.

Digital camera/Web cam

These are input devices that input still images or video to computer.

4. Summary

In this topic we have learnt:

x     What is computer mouse?

x     How to do clicking, double clicking, right clicking and dragging with mouse?

x     What is mouse pointer?

x     Some other devices e.g track pad, track ball, joystick

x     Input devices for image(Scanner), sound(Microphone), Video(Digital camera, webcam)

5. Exercise

Survey the market and find four different models of microphone that are used to input the voice into computer. Write their names and numbers.

What are the different devices through which we can input video to a computer?