Computer Hardware - SSS 1

COMPUTER HARDWARE

Subject: Digital Technologies
Class: SSS 1
Term: First Term
Week: 4
Topic: Computer Hardware
Duration: 80 Minutes (Double Period)

LEARNING OBJECTIVES

By the end of the lesson, students should be able to:

Define computer hardware.
Identify common computer hardware devices.
Explain the functions of input devices.
Identify and describe common output devices.
Explain the purpose of storage devices.
Differentiate between primary and secondary storage.
Identify common storage devices used in computers.
Explain the difference between system devices and peripheral devices.
Classify common computer devices according to their functions.
Explain the importance of hardware in the operation of a computer system.

1. INTRODUCTION

A computer system is made up of different physical and non-physical components that work together to perform useful tasks. The physical components that can be seen and touched are known as computer hardware.

For example, when a student types information using a keyboard, views information on a monitor, stores a document on a flash drive, or prints a document using a printer, different hardware devices are involved.

Definition:
Computer hardware refers to the physical parts or components of a computer system that can be seen and touched.

Hardware cannot perform useful computing tasks by itself. It works together with software and other components of the computer system. For example, a keyboard provides a means of entering data, while software processes the information entered.

2. TYPES / CATEGORIES OF COMPUTER HARDWARE

Computer hardware can be classified according to the functions performed by the different devices. The major categories include:

Input devices
Output devices
Storage devices
System devices
Peripheral devices

3. INPUT DEVICES

An input device is a hardware device used to enter data and instructions into a computer system for processing.

Input Device:
An input device is a hardware component through which data and instructions are entered into a computer.

3.1 Keyboard

A keyboard is an input device containing keys used to enter letters, numbers, symbols and instructions into a computer.

Examples of keyboard keys include:

Alphabet keys
Number keys
Function keys
Arrow keys
Control keys
Enter key
Spacebar
Backspace key

3.2 Mouse

A mouse is a pointing input device used to control the movement of the pointer on a computer screen. It is commonly used for pointing, clicking, selecting, dragging and opening items.

3.3 Scanner

A scanner is an input device used to capture pictures, photographs or printed documents and convert them into digital form that can be processed or stored by a computer.

3.4 Microphone

A microphone is an input device used to capture sound and send it into a computer or other digital device.

It can be used for voice recording, online meetings, voice communication and speech recognition.

3.5 Webcam

A webcam is a camera that captures images and video and sends them to a computer. It is commonly used for video calls, online classes and video recording.

3.6 Touchscreen

A touchscreen is a display that allows the user to interact with a computer or digital device by touching areas of the screen.

A touchscreen can serve as both an input and an output device because it displays information and also accepts user input.

3.7 Other Input Devices

Other examples of input devices include:

Joystick
Light pen
Graphics tablet
Barcode reader
Biometric scanner
Card reader
Digital camera

3.8 Summary of Input Devices

Input Device	Function
Keyboard	Used to enter text, numbers, symbols and commands.
Mouse	Used for pointing, selecting, clicking and dragging.
Scanner	Converts printed documents and images into digital form.
Microphone	Captures sound and voice.
Webcam	Captures images and video.
Touchscreen	Accepts input through touch.
Joystick	Provides directional control, especially in games and simulations.
Biometric scanner	Captures biological characteristics such as fingerprints for identification.

4. OUTPUT DEVICES

An output device is a hardware device used to present or produce the results of data processing in a form that can be understood by the user.

Output Device:
An output device is a hardware component that receives processed information from a computer and presents the result to the user.

4.1 Monitor

A monitor is a display device that presents text, pictures, video and other visual information produced by a computer.

Common types include LCD, LED and other modern flat-panel displays.

4.2 Printer

A printer is an output device that produces a physical copy of information from a computer on paper or another suitable material.

The physical output produced by a printer is called a hard copy.

Common types of printers include:

Inkjet printer
Laser printer
Dot-matrix printer

4.3 Speakers

Speakers are output devices that produce sound from a computer. They are used for listening to music, speech, videos, alerts and other audio information.

4.4 Headphones

Headphones are audio output devices worn over or around the ears. They allow a user to listen to sound from a computer without using external speakers.

4.5 Projector

A projector is an output device that displays computer information such as text, images and video on a larger screen or surface. It is commonly used in classrooms, offices and presentations.

4.6 Other Output Devices

Plotter
Interactive display
Braille embosser

4.7 Summary of Output Devices

Output Device	Function
Monitor	Displays text, images, video and other visual information.
Printer	Produces information on paper or other physical media.
Speakers	Produce sound from the computer.
Headphones	Provide personal audio output.
Projector	Displays computer information on a large screen or surface.
Plotter	Produces large, precise drawings and graphics.

5. STORAGE DEVICES

Storage devices are hardware components used to store data, programs and information for future use. Stored information can be retrieved when it is needed.

Storage Device:
A storage device is a hardware component used to record, retain and retrieve digital data and information.

Storage is important because data entered into a computer and information produced by a computer may need to be kept for later use.

5.1 Primary Storage

Primary storage refers to memory that is directly accessible by the processor and is used during the operation of a computer.

RAM (Random Access Memory)

RAM is a type of primary memory used to temporarily hold data and instructions that the computer is currently using.

Important: RAM is generally volatile memory. This means that information stored in RAM is lost when power is removed from the computer.

ROM (Read-Only Memory)

ROM is a type of memory that stores instructions needed for basic computer operations. Unlike RAM, its contents are designed to remain available when the computer is switched off.

5.2 Secondary Storage

Secondary storage is used to store data and programs for longer-term use. It normally retains information even when the computer is switched off.

Examples of secondary storage devices include:

Hard Disk Drive (HDD)
Solid-State Drive (SSD)
USB flash drive
Memory card
Optical disc
External hard drive

5.3 Hard Disk Drive (HDD)

A hard disk drive is a storage device that uses magnetic disks to store digital information. It can be used to store the operating system, applications, documents, pictures, videos and other files.

5.4 Solid-State Drive (SSD)

A solid-state drive is a storage device that uses electronic memory chips to store data. It has no moving magnetic disks and is commonly used in modern computers.

5.5 USB Flash Drive

A USB flash drive is a small portable storage device that uses flash memory. It can be connected to a computer through a USB port to store or transfer files.

5.6 Memory Card

A memory card is a small removable storage device commonly used in smartphones, digital cameras, tablets and other portable devices.

5.7 Optical Disc

An optical disc stores information using laser technology. Examples include CDs, DVDs and Blu-ray discs.

5.8 Comparison of Primary and Secondary Storage

Feature	Primary Storage	Secondary Storage
Use	Provides fast access to data and instructions needed during processing.	Provides longer-term storage of data and programs.
Examples	RAM and ROM	HDD, SSD, flash drive and memory card
Capacity	Generally smaller than secondary storage.	Generally available in larger capacities.
Portability	Usually installed inside or closely associated with the computer.	Some types can easily be removed and transported.

6. SYSTEM DEVICES

System devices are hardware components that are essential to the basic operation and processing activities of a computer system.

6.1 Central Processing Unit (CPU)

The Central Processing Unit (CPU) is the main processing component of a computer. It executes instructions and performs calculations and logical operations.

The CPU is commonly described in terms of major components such as:

Arithmetic and Logic Unit (ALU): Performs arithmetic calculations and logical operations.
Control Unit (CU): Controls and coordinates the activities of the computer system.
Registers: Small, fast storage locations used by the processor while processing data and instructions.

6.2 Motherboard

The motherboard is the main circuit board of a computer. It provides connections through which the processor, memory, storage devices and other components communicate.

6.3 System Memory

System memory, particularly RAM, provides temporary working space for programs and data that are being actively used by the computer.

6.4 Power Supply Unit

The Power Supply Unit (PSU) supplies the electrical power required by the internal components of a desktop computer.

Note: System devices are important for the basic operation, processing, communication and control of a computer system. A computer may also have many additional devices connected to extend its functions.

7. PERIPHERAL DEVICES

A peripheral device is a hardware device connected to a computer to provide additional input, output, storage or communication functions.

Some peripheral devices are external to the main computer system and can usually be connected or removed when required.

Examples include:

Keyboard
Mouse
Printer
Scanner
Webcam
External speakers
External storage drives
Projector
Game controller

Important: The terms "system device" and "peripheral device" describe the role of hardware in relation to the computer system. A device can also be classified by its function, such as input, output or storage. Therefore, classifications can overlap. For example, a keyboard is an input device and may also be used as a peripheral device.

8. DIFFERENCE BETWEEN INPUT, OUTPUT, STORAGE AND SYSTEM DEVICES

Category	Main Function	Examples
Input Devices	Enter data and instructions into the computer.	Keyboard, mouse, scanner, microphone
Output Devices	Present processed information to the user.	Monitor, printer, speakers, projector
Storage Devices	Store data, programs and information.	HDD, SSD, flash drive, memory card
System Devices	Support processing, control, communication and basic operation of the computer.	CPU, motherboard, RAM, power supply
Peripheral Devices	Extend the functions of a computer by providing additional input, output, storage or communication capabilities.	Keyboard, mouse, printer, scanner, webcam

9. IMPORTANCE OF COMPUTER HARDWARE

Computer hardware is important because it:

Provides a means of entering data and instructions.
Processes data and executes instructions.
Displays and produces processed information.
Stores data, programs and information for future use.
Allows users to communicate with computer systems.
Supports connection to networks and other digital devices.
Enables computers to perform different tasks in education, business, healthcare, communication and other areas.

10. CLASS ACTIVITY

Activity 1: Identify the hardware.

The teacher displays or provides pictures of different computer hardware devices. Students work in groups to identify each device and classify it as an input, output, storage, system or peripheral device where appropriate.

Activity 2: Hardware classification.

Device	Category	Function
Keyboard	Input / Peripheral	Enters text, numbers and commands.
Monitor	Output	Displays information.
USB Flash Drive	Storage / Peripheral	Stores and transfers files.
CPU	System Device	Processes instructions and data.

11. SUMMARY

Computer hardware refers to the physical components of a computer system that can be seen and touched. Hardware performs different functions and can be grouped according to its role.

Input devices are used to enter data and instructions, while output devices present the results of processing. Storage devices are used to keep data and programs for present or future use. System devices support the basic operation and processing of the computer, while peripheral devices extend the functions of the computer.

Examples of hardware include keyboards, mice, monitors, printers, scanners, CPUs, motherboards, hard drives, solid-state drives and USB flash drives. These components work together with software to make a computer system useful.

12. EVALUATION

Define computer hardware.
What is an input device?
Mention five input devices and state one function of each.
What is an output device?
Mention four output devices.
Differentiate between a monitor and a printer.
What is a storage device?
Differentiate between primary and secondary storage.
Mention four secondary storage devices.
What is the function of the CPU?
State two functions of the motherboard.
What is a peripheral device?
Give four examples of peripheral devices.
Classify the following as input, output, storage or system devices: keyboard, monitor, SSD, scanner, CPU and printer.
Explain why computer hardware is important to a computer system.

13. ASSIGNMENT

Define computer hardware and explain its importance.
Draw and label any five computer hardware devices.
Prepare a table showing ten computer hardware devices, their categories and their functions.
Explain the difference between input devices and output devices, giving four examples of each.
Differentiate between primary storage and secondary storage and give two examples of each.
Explain the difference between system devices and peripheral devices.