Keyboard and mouse are two of the most commonly used input devices. They allow users to enter data, give commands, select items and control software applications.

A keyboard is mainly used to enter text, numbers and commands.
A mouse is mainly used to control the pointer and interact with graphical elements on the screen.

Both devices convert the user’s physical actions into digital signals that the computer can understand.

What Is a Keyboard?

A keyboard is an input device used to enter text, numbers, symbols and commands into a computer.

It contains a collection of keys. Each key performs a particular function or represents a character.

Keyboards are commonly used with:

Desktop computers
Laptops
Tablets
Smartphones
Gaming consoles
Smart televisions
ATMs and other electronic systems

How Does a Keyboard Work?

When a user presses a key:

A switch beneath the key is activated.
The keyboard identifies which key was pressed.
It creates a digital code known as a scan code.
The code is sent to the computer.
The operating system interprets the code.
The appropriate character or command appears on the screen.

For example, when the letter A is pressed, the keyboard sends the corresponding signal to the computer. The active application then displays or uses the letter.

Main Sections of a Keyboard

A standard keyboard is divided into several groups of keys.

Alphanumeric Keys

Alphanumeric keys include letters, numbers, punctuation marks and symbols.

They include:

Letters from A to Z
Numbers from 0 to 9
Comma and full stop
Question mark
Brackets
Other special symbols

These keys are mainly used for typing.

Function Keys

Function keys are located along the top of many keyboards and are labelled from F1 to F12.

Their exact purpose depends on the operating system and application.

Common examples include:

F1: Opens help in many applications
F2: Renames a selected file in Windows
F5: Refreshes a page or window
F11: Activates full-screen mode in many browsers

Some laptops require the Fn key to use certain function-key commands.

Control Keys

Control keys are used alone or with other keys to perform commands.

Examples include:

Ctrl
Alt
Esc
Windows key
Command key on Apple keyboards
Menu key

For example, pressing Ctrl and C together copies selected content in many applications.

Navigation Keys

Navigation keys move the cursor or selection through a document, web page or menu.

Examples include:

Arrow keys
Home
End
Page Up
Page Down

Numeric Keypad

The numeric keypad is normally located on the right side of a full-size keyboard.

It contains:

Numbers from 0 to 9
Addition key
Subtraction key
Multiplication key
Division key
Decimal key
Enter key

The Num Lock key enables or changes the function of the numeric keypad.

Compact keyboards and many laptops may not include a separate numeric keypad.

Important Keyboard Keys and Their Functions

Key	Function
Enter	Starts a new line or confirms a command
Spacebar	Inserts a blank space
Backspace	Removes the character to the left of the cursor
Delete	Removes selected content or the character to the right
Shift	Produces capital letters or upper symbols when held
Caps Lock	Keeps letter keys in uppercase mode
Tab	Moves to the next field or creates indentation
Ctrl	Works with other keys to perform commands
Alt	Activates alternative commands and shortcuts
Esc	Cancels or closes the current operation
Arrow Keys	Move the cursor or selection
Home	Moves to the beginning of a line or section
End	Moves to the end of a line or section
Print Screen	Captures the screen on many computers
Windows Key	Opens Windows features and shortcuts
Fn	Activates additional laptop-key functions

Common Keyboard Shortcuts

Keyboard shortcuts allow users to perform tasks quickly.

Shortcut	Common Function
Ctrl + C	Copy
Ctrl + V	Paste
Ctrl + X	Cut
Ctrl + Z	Undo
Ctrl + Y	Redo
Ctrl + A	Select all
Ctrl + S	Save
Ctrl + P	Print
Ctrl + F	Find text
Alt + Tab	Switch between open applications
Ctrl + Alt + Delete	Opens security options in Windows
Windows + L	Locks a Windows computer

Shortcuts may work differently depending on the operating system and application.

Types of Keyboard

Standard Keyboard

A standard keyboard contains alphanumeric keys, function keys, navigation keys and a numeric keypad.

It is commonly used with desktop computers.

Laptop Keyboard

A laptop keyboard is built into the laptop.

It is usually smaller and may combine several functions into the same keys to save space.

Membrane Keyboard

A membrane keyboard uses flexible membrane layers beneath the keys.

It is:

Affordable
Quiet
Lightweight
Commonly used in offices and homes

Its keys may feel softer than those of a mechanical keyboard.

Mechanical Keyboard

A mechanical keyboard uses a separate mechanical switch beneath each key.

It generally provides:

Clear key feedback
High durability
Replaceable keycaps on many models
Different switch options
A popular choice for typing and gaming

Mechanical keyboards are often more expensive and louder than membrane keyboards.

Chiclet Keyboard

A chiclet keyboard has flat, separated keys with small spaces between them.

It is commonly found in modern laptops and slim desktop keyboards.

Ergonomic Keyboard

An ergonomic keyboard is designed to provide a more natural hand and wrist position.

It may contain:

A curved design
A split layout
A wrist rest
Angled key sections

An ergonomic design may improve comfort, but correct posture and regular breaks are still important.

Gaming Keyboard

A gaming keyboard may provide:

Customisable lighting
Programmable keys
Fast key response
Anti-ghosting
Multiple-key detection
Mechanical switches

Gaming features vary between different models.

Wireless Keyboard

A wireless keyboard communicates with the computer through:

Bluetooth
A wireless USB receiver

It reduces cable clutter but requires a battery or regular charging.

Virtual Keyboard

A virtual keyboard appears on a touchscreen or computer display.

Users enter information by touching or selecting keys on the screen.

Virtual keyboards are commonly used on smartphones, tablets, kiosks and accessibility systems.

Common Keyboard Layouts

A keyboard layout determines the position of letters, numbers and symbols.

QWERTY

QWERTY is the most commonly used English keyboard layout. Its name comes from the first six letter keys in the top row.

AZERTY

AZERTY is commonly used in France and some other French-speaking regions.

QWERTZ

QWERTZ is used in Germany and some Central European countries.

Dvorak

The Dvorak layout was designed to reduce finger movement during English typing, but it is less common than QWERTY.

Keyboard Connection Types

A keyboard can connect to a computer through:

USB

USB is the most common wired keyboard connection.

PS/2

PS/2 is an older circular connector found on some desktop motherboards.

Bluetooth

Bluetooth allows a keyboard to connect wirelessly without a cable.

Wireless USB Receiver

Some wireless keyboards use a small receiver connected to a USB port.

Uses of a Keyboard

A keyboard is used for:

Writing documents
Entering numbers
Searching the internet
Writing emails
Programming
Entering passwords
Playing games
Controlling applications
Using keyboard shortcuts
Navigating without a mouse

Advantages of a Keyboard

Provides fast text entry
Offers accurate data entry
Supports useful shortcuts
Available in many sizes and layouts
Suitable for professional work
Can control a computer without a mouse
Widely supported by operating systems

Limitations of a Keyboard

Requires typing knowledge
Extended use may cause discomfort
Physical keyboards require desk space
Keys can collect dust and stop working
Different layouts may confuse users
Wireless models require power
It is less suitable than a mouse for drawing and pointer control

What Is a Mouse?

A mouse is a pointing input device used to control the movement of a pointer on a computer screen.

Moving the mouse across a surface moves the pointer in the corresponding direction.

A mouse allows users to:

Select icons
Open files
Click buttons
Drag objects
Scroll through pages
Draw and edit content
Interact with menus

The mouse is an important part of a graphical user interface.

How Does a Mouse Work?

A modern optical mouse contains a light source, sensor and processor.

When the mouse moves:

A light illuminates the surface beneath the mouse.
The optical sensor captures many images of the surface.
The mouse processor compares these images.
It calculates the direction and distance of movement.
Movement data is sent to the computer.
The pointer moves on the screen.

When a button is pressed, the mouse sends an additional signal that identifies the selected button or action.

Main Parts of a Mouse

Left Button

The left button is commonly used to:

Select items
Open files
Press on-screen buttons
Place the text cursor
Drag objects

Right Button

The right button normally opens a shortcut or context menu containing additional options.

Scroll Wheel

The scroll wheel moves a page or document up and down.

On many mice, the wheel can also be pressed as a middle button.

Optical Sensor

The sensor detects the movement of the mouse across a surface.

Additional Buttons

Some mice contain additional buttons for:

Moving forwards and backwards
Changing sensitivity
Gaming commands
Application shortcuts

Cable, Receiver or Bluetooth Module

A mouse may communicate with the computer using a cable, wireless receiver or Bluetooth connection.

Battery

Wireless mice require replaceable batteries or an internal rechargeable battery.

Common Mouse Actions

Pointing

Pointing means moving the pointer over an item on the screen.

Single-Clicking

A single click is normally used to select an item or activate a button.

Double-Clicking

A double click means pressing the left mouse button twice quickly. It commonly opens files, folders and applications.

Right-Clicking

Right-clicking normally opens a menu containing options related to the selected item.

Dragging and Dropping

Dragging and dropping involves:

Pressing and holding the left button over an item
Moving the mouse
Releasing the button at a new location

It can be used to move files, resize windows and arrange objects.

Scrolling

Scrolling moves through a document, web page or menu.

Hovering

Hovering means placing the pointer over an item without clicking. It may display additional information or activate a visual effect.

Types of Mouse

Mechanical Mouse

A mechanical mouse uses a rubber or metal ball to detect movement.

As the ball rotates, internal rollers measure its direction.

Mechanical mice are now rarely used because they collect dust and are less accurate than modern optical mice.

Optical Mouse

An optical mouse uses an LED light and image sensor to detect movement.

It is:

Accurate
Affordable
Reliable
Commonly used with modern computers

Laser Mouse

A laser mouse uses laser illumination instead of a standard LED.

It can provide high sensitivity and may work on a wider range of surfaces. Performance depends on the individual model and surface.

Wired Mouse

A wired mouse connects directly to a computer, normally through USB.

It provides:

A stable connection
No need for batteries
Low input delay
Simple installation

The cable may reduce portability or create desk clutter.

Wireless Mouse

A wireless mouse connects using Bluetooth or a USB wireless receiver.

It provides:

Greater portability
Less cable clutter
Flexible movement

It requires batteries or charging and may occasionally experience wireless interference.

Gaming Mouse

A gaming mouse may include:

High sensitivity
Adjustable DPI
Additional buttons
Customisable lighting
Programmable commands
Adjustable weight
High polling rates

These features are designed to provide greater control in games and specialised applications.

Ergonomic Mouse

An ergonomic mouse is designed to support a more natural hand and wrist position.

Common designs include:

Vertical mouse
Sculpted mouse
Angled mouse
Thumb-operated pointing device

Comfort depends on the user’s hand size, grip and working position.

Trackball

A trackball is a pointing device containing a ball that the user rotates with a finger or thumb.

Unlike a normal mouse, the device itself remains stationary.

It is useful where desk space is limited, although it is more accurately described as an alternative pointing device rather than a traditional mouse.

What Is Mouse DPI?

DPI stands for Dots Per Inch.

In everyday mouse settings, DPI describes how far the pointer moves in relation to the physical movement of the mouse.

A higher DPI moves the pointer farther with less hand movement.
A lower DPI provides slower and more controlled pointer movement.

A higher DPI does not automatically mean that a mouse is better or more accurate. The best setting depends on the screen, task and personal preference.

Mouse Connection Types

A mouse can connect through:

USB cable
PS/2 connector
Bluetooth
Wireless USB receiver

Modern computers mainly use USB and Bluetooth connections.

Uses of a Mouse

A mouse is used for:

Selecting files and folders
Opening applications
Navigating websites
Drawing and designing
Editing photos and videos
Playing games
Resizing windows
Moving on-screen objects
Scrolling through documents
Accessing menus and controls

Advantages of a Mouse

Easy to learn
Provides quick pointer control
Makes graphical interfaces easier to use
Useful for drawing and design
Supports clicking, scrolling and dragging
Available in wired and wireless versions
Can include programmable buttons

Limitations of a Mouse

Requires a suitable working surface
Repeated use may cause discomfort
Not ideal for entering text
Wireless models require power
Sensors may not work correctly on some surfaces
Cables can restrict movement
Pointer control may be difficult for some users

Difference Between Keyboard and Mouse

Feature	Keyboard	Mouse
Device Type	Input device	Pointing input device
Main Purpose	Enters text, numbers and commands	Controls the on-screen pointer
User Action	Pressing keys	Moving, clicking and scrolling
Best For	Typing and keyboard shortcuts	Selecting and moving graphical objects
Main Components	Character, function and control keys	Buttons, wheel and movement sensor
Common Connection	USB, Bluetooth or wireless receiver	USB, Bluetooth or wireless receiver
Can Work Alone	Can control many functions without a mouse	Not suitable for normal text entry

How Keyboard and Mouse Work Together

The keyboard and mouse perform different but complementary tasks.

For example, while editing a document:

The keyboard enters text.
The mouse selects text and menu options.
Keyboard shortcuts perform commands quickly.
The mouse changes the pointer position.
Both devices help the user control the application.

A computer can be operated using only a keyboard in many situations, but using both devices is generally easier for graphical applications.

Keyboard and Mouse Accessibility Features

Operating systems provide accessibility features for users who find standard input devices difficult to use.

Examples include:

On-screen keyboard
Sticky Keys
Filter Keys
Mouse Keys
Pointer-speed adjustment
Larger mouse pointers
High-contrast pointer colours
Voice typing
Alternative and adaptive keyboards
Specialised switches and pointing devices

These features can make computers easier to use for people with mobility, vision or coordination difficulties.

How to Maintain a Keyboard and Mouse

Keyboard Maintenance

Disconnect the keyboard before cleaning.
Remove loose dust carefully.
Avoid eating or drinking over the keyboard.
Do not use excessive liquid.
Keep the cable and connector protected.
Replace batteries in wireless keyboards when required.

Mouse Maintenance

Clean the sensor gently.
Use a clean and suitable surface.
Remove dust from the scroll wheel.
Protect the cable from damage.
Replace or charge wireless-mouse batteries.
Keep the USB receiver in a safe location.

Frequently Asked Questions

Is a keyboard an input or output device?

A keyboard is an input device because it sends text, numbers and commands to the computer.

Is a mouse an input or output device?

A mouse is an input device because it sends movement and button commands to the computer.

What is the main function of a keyboard?

The main function of a keyboard is to enter text, numbers, symbols and commands.

What is the main function of a mouse?

The main function of a mouse is to control the pointer and interact with graphical items on the screen.

Which keyboard layout is most common?

QWERTY is the most commonly used English keyboard layout.

What is the difference between an optical and mechanical mouse?

An optical mouse uses light and a sensor, while a mechanical mouse uses a rolling ball to detect movement.

Which is better, a wired or wireless mouse?

A wired mouse provides a stable connection without batteries. A wireless mouse provides greater portability and reduces cable clutter. The better choice depends on the user’s needs.

What is a mechanical keyboard?

A mechanical keyboard uses an individual mechanical switch beneath each key.

Can a computer work without a mouse?

Yes. Many computer functions can be controlled using a keyboard, keyboard shortcuts or another pointing device.

Can a computer work without a physical keyboard?

Yes. A computer or touchscreen device can use an on-screen keyboard, voice input or another supported input method.

Conclusion

Keyboard and mouse are essential input devices used to control computers.

A keyboard enters text, numbers, symbols and commands through different groups of keys. A mouse controls the on-screen pointer through movement, clicks and scrolling.

In simple words:

Use the keyboard for typing and commands.
Use the mouse for pointing, selecting and navigating.

Together, the keyboard and mouse make it easier to communicate with a computer and control software applications.