2. Computer Hardware

🔹 2. Computer Hardware

2.1 Introduction to Computer Hardware

Computer Hardware refers to the physical parts of a computer system that we can see and touch. Without hardware, a computer cannot function.

👉 Simple Definition (Exam Friendly):

Computer hardware is the collection of physical components of a computer system.

🧠 Examples:

Keyboard

Mouse

Monitor

CPU

Hard Disk

Printer

Plotter

📌 Hardware works together with software to perform tasks.

2.2 Classification of Computer Hardware

Computer hardware can be broadly classified into:

Input Devices

Output Devices

Storage Devices

Processing Devices (CPU)

Memory Devices (RAM)

Motherboard

🔹 2.3 Input Devices

What are Input Devices?

Input devices are hardware components used to enter data and instructions into the computer.

👉 Definition:

Input devices are used to feed data into a computer for processing.

2.3.1 Keyboard

Description:

A keyboard is the most commonly used input device. It is used to type text, numbers, and commands.

Key Features:

Contains alphabet keys (A–Z)

Numeric keys (0–9)

Function keys (F1–F12)

Control keys (Ctrl, Alt, Shift)

Arrow keys

Uses:

Typing documents

Entering data

Writing exams online

Types of Keyboards:

Standard keyboard

Multimedia keyboard

Wireless keyboard

📌 Most commonly used input device

2.3.2 Mouse

Description:

A mouse is a pointing input device used to select, click, drag, and scroll items on the screen.

Key Functions:

Left click

Right click

Scroll wheel

Drag and drop

Types of Mouse:

Mechanical mouse

Optical mouse

Wireless mouse

Advantages:

Easy navigation

Faster selection

User-friendly

📌 Widely used in Windows operating systems

2.3.3 Scanner

Description:

A scanner is an input device used to convert physical documents or images into digital format.

Uses:

Scanning certificates

Uploading documents online

Digital storage of paper records

Types of Scanners:

Flatbed scanner

Handheld scanner

Barcode scanner

📌 Commonly used in government offices and banks

🔹 2.4 Output Devices

What are Output Devices?

Output devices are hardware components used to display or produce results from the computer.

👉 Definition:

Output devices present processed data to the user.

2.4.1 Monitor

Description:

A monitor is the primary output device that displays text, images, and videos.

Types of Monitors:

CRT (old type)

LCD

LED

Features:

Resolution

Screen size

Refresh rate

Uses:

Viewing documents

Watching videos

Online exams

📌 Also called Visual Display Unit (VDU)

2.4.2 Printer

Description:

A printer produces hard copy output on paper.

Types of Printers:

Impact Printers

Dot matrix

Non-Impact Printers

Inkjet

Laser

Uses:

Printing documents

Exam hall tickets

Office records

📌 Laser printers are fast and commonly used in offices.

2.4.3 Speakers

Description:

Speakers are output devices used to produce sound output.

Uses:

Listening to audio

Video conferencing

Online classes

Types:

Wired speakers

Wireless speakers

📌 Often used with multimedia applications

🔹 2.5 Storage Devices

What are Storage Devices?

Storage devices are used to store data permanently or temporarily.

Types of Storage:

Primary Storage

Secondary Storage

2.5.1 Hard Disk Drive (HDD)

Description:

A Hard Disk Drive (HDD) is a secondary storage device used for permanent data storage.

Features:

Large storage capacity

Magnetic storage

Slower than SSD

Uses:

Storing OS

Software applications

Files and folders

📌 Found inside desktop computers

2.5.2 Solid State Drive (SSD)

Description:

An SSD is a modern storage device that uses flash memory.

Advantages:

Faster than HDD

No moving parts

Less power consumption

Disadvantages:

More expensive

📌 Used in modern laptops and high-speed systems

2.5.3 USB Flash Drive (Pen Drive)

Description:

A USB drive is a portable storage device.

Features:

Small size

Easy to carry

Plug and play

Uses:

File transfer

Backup storage

📌 Very common in exams and offices

🔹 2.6 Central Processing Unit (CPU)

What is CPU?

The CPU is the brain of the computer. It performs all calculations and controls operations.

👉 Definition:

CPU is the main processing unit that executes instructions.

Components of CPU:

1. Arithmetic Logic Unit (ALU)

Performs arithmetic operations

Performs logical operations

2. Control Unit (CU)

Controls data flow

Manages execution of instructions

3. Registers

Small, fast memory

Stores temporary data

📌 CPU speed is measured in GHz

🔹 2.7 Random Access Memory (RAM)

What is RAM?

RAM is the primary memory used to store data temporarily.

Features:

Volatile memory

Fast access

Data lost when power off

Types of RAM:

DRAM

SRAM

Importance:

More RAM → better performance

Used by running applications

📌 Essential for multitasking

🔹 2.8 Motherboard

What is Motherboard?

The motherboard is the main circuit board of the computer.

Functions:

Connects all components

Allows communication between hardware

Houses CPU, RAM, ports

Components on Motherboard:

CPU socket

RAM slots

Expansion slots

Ports (USB, HDMI)

📌 Without motherboard, hardware cannot communicate

🔹 2.9 Comparison Table (Important for Exams)

Component                                  Function

Keyboard                                     Input text

Mouse.                                           Pointing

Monitor                                           Display

Printer                                          Hard copy

HDD                                               Storage

SSD                                                 Fast storage

CPU                                                   Processing

RAM                                            Temporary memory

Motherboard                                   Connectivity

🔹 2.10 Importance of Computer Hardware for KPSC Exam

KPSC often asks: ✔ Definitions

✔ Functions

✔ Difference between HDD & SSD

✔ CPU components

✔ RAM characteristics

✅ Final Exam Tips

Learn definitions

Remember functions

Understand differences

Practice MCQs daily