Lecture 2: Hardware components of a

Computers

Lecture 2: Hardware
Components of a
computer
BY:

SNR. LECTURER NIDA KHALID

S U B J E C T:

I N T R O D U C T I O N T O I N F O R M AT I O N A N D C O M M U N I C AT I O N T E C H N O L O G Y ( I C T )

INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 1

 Lecture Outline
This lecture covers:
◦ Components of a computer
◦ CPU
◦ Input devices
◦ Output devices

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 2
 Lecture 2: Hardware components of a
Computers

Basic operations
◦ Input: Entering data into the computer
◦ Processing: Performing operations on
the data
◦ Output: Presenting the results
◦ Storage: Saving data, programs, or
output for future use
◦ Communications: Sending or receiving
data

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Anatomy of Computer
oInput Device
oCentral Processing
Unit
oOutput Device

Block Diagram of computer

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 4
Computer Units and their Functions
Computer Units Function

Input Device Read information from media and enter

to computer in coded form
CPU(Memory unit, Athematic logic Store program and Data,
Unit, Control Unit) Perform arithmetic and logic functions ,
Interprets program instructions and
control the input and output device.

Output Device Decodes information and present to

user

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 5
Input Devices
Input Devices: Devices User to
provide Data and Instruction
to the computer.
Example Mouse, keyboard,
scanner, etc.

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Input Devices
Keyboard
◦ Primary device for typing text, numbers, and
symbols.
◦ Types of keys:
◦ Alphanumeric keys
◦ Function keys (F1-F12)
◦ Special keys (Ctrl, Alt, etc.)
◦ Common in almost every computing device
(desktop, laptop, etc.).

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 7
Input Devices
Mouse
◦ Pointing device used for navigating the graphical
user interface (GUI).
◦ Types:
◦ Optical Mouse (uses light sensors).
◦ Mechanical Mouse (older, uses a rolling ball).
◦ Functions:
◦ Moving the pointer, clicking, dragging, and scrolling.

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Input Devices

Touchscreen
o
Input and display device combined in one.
o
Allows users to interact by touching the screen
directly.
o
Used in smartphones, tablets, and ATMs.
o
Supports multi-touch gestures (pinch-to-zoom,
swipe).

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 9
Input Devices
Scanner
◦ Device that captures images, text, or documents
and converts them into a digital format.
◦ Types:
◦ Flatbed Scanners (most common for documents).
◦ Handheld Scanners (portable).
◦ Barcode Scanners (used in retail for product codes).
◦ Used in digitizing documents, photos, and barcodes.

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 10
Input Devices

Microphone
o
Captures sound and converts it into digital signals.
Used for:
o
Voice recording.
o
Speech recognition software.
o
Video conferencing and online communication.

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Input Devices
Camera
o
Captures still images or video and converts them into
digital format.
o
Webcams are integrated into laptops or can be external
devices.
o
Used for video calls, photography, and streaming.

Other input devices

o
Stylus (used with touchscreens or drawing tablets)
o
Specialized input device used for playing video games
such as Joysticks, gamepads, steering wheels.
o
Trackball (a stationary pointing device with a rolling
ball).
o
Biometric Devices (fingerprint scanners, facial
recognition).
o
Light Pen (used in graphic design or CAD systems).

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Output Devices

Output Devices: Computer output devices are hardware components that

allow computers to communicate information or data to users or other
devices. These devices convert digital data generated by the computer into
human- readable forms, visual displays, or physical outputs. Example Printer,
Monitor, etc.

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Output Devices
Monitor
o
Primary visual output device for displaying text, images,
videos, and graphical interfaces.
o
Types: CRT (Cathode Ray Tube): Older, bulky monitors.
o
LCD/LED: Flat-screen, energy-efficient modern monitors.
o
Touchscreen Monitors: Serve as both input and output
devices.
o
Used in desktops, laptops, and professional workstations.

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Output Devices
Printer
o
Converts digital documents into hard copies on paper.
Types:
o
Inkjet Printer: Sprays tiny droplets of ink to create images
and text.
o
Laser Printer: Uses a laser beam to print text/images quickly.
o
3D Printers: Create physical objects by adding material layer
by layer.
o
Used for documents, photographs, and physical models..

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Output Devices
Speakers
o
Audio output devices that convert digital sound signals into
audible sounds.
o
Used for music, voice, video calls, and multimedia content.
o
Can be external (connected via cables) or integrated into
devices like laptops, smartphones.
o
Supports stereo and surround sound for enhanced audio
experiences.

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Output Devices
Headphones
o
Personal audio output device, similar to speakers but worn
on the ears.
o
Types:
o
Wired headphones.
o
Wireless (Bluetooth) headphones.
o
Used for private listening, such as music, phone calls, and
online meetings.

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Output Devices
Projectors
o
Device that projects visual content (images, presentations,
videos) onto a large screen or surface.
o
Used in meetings, classrooms, and cinemas.
o
Modern projectors are often LED or laser-based for higher
resolution and brightness.

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Central Processing Unit
o
The CPU (Central Processing Unit) is the primary
component of a computer that performs most of
the processing inside a computer.
o
Known as the "brain" of the computer because it
executes instructions from programs and manages
other hardware components.
Its main functions are:
o
Fetch: Retrieves instructions from memory.
o
Decode: Translates instructions into commands the
computer understands.
o
Execute: Carries out the commands.
o
Store: Writes the result back to memory if needed.

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Central Processing Unit
Main Components
Arithmetic Logic Unit (ALU):
Performs arithmetic (addition, subtraction) and logical operations (comparisons).
Control Unit (CU):
Directs the operation of the CPU and tells the other parts of the computer how to respond to
instructions.
Registers:
Small, high-speed storage locations for temporarily holding data and instructions during
processing.

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CPU motherboard
Computer ports
A connection point that acts as interface between the
computer and external devices like mouse, printer,
modem, etc. is called port.
Ports are of two types:
Internal port − It connects the motherboard to internal
devices like hard disk drive, CD drive, internal modem,
etc.
External port − It connects the motherboard to external
devices like modem, mouse, printer, flash drives, etc.
Computer port
Serial Port
Serial ports transmit data sequentially one bit at a time.
So they need only one wire to transmit 8 bits.
However it also makes them slower.
Serial ports are usually 9-pin or 25-pin male connectors.
They are also known as COM (communication) ports or RS323C ports.
Example: mouse and keyboard use serial port.
Serial Port
Parallel Port
A parallel port is able to transmit multiple data streams at a
time.
It sends data by sending multiple bits in parallel fashion.
Parallel ports can send or receive 8 bits or 1 byte at a time.
Parallel ports come in form of 25-pin female pins and are used
to connect printer, scanner, external hard disk drive, etc.
Example: printer use parallel port.
Parallel Port
System buses
 A system bus is a communication
pathway used for data transmission
between various components of a
computer.
It connects the CPU, memory, and
input/output (I/O) devices.
Acts as a communication highway for
data and instructions within the
computer system.

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System buses
Data Bus −
Lines that carry data to and from memory are called data bus.
The width of the data bus (number of lines) determines how much data can
be transferred at once, e.g., 32-bit or 64-bit.
Larger data buses result in faster data transfer.

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System buses
Address Bus −
It is a unidirectional responsible for carrying address of a memory location or I/O port
from CPU to memory or I/O port.
Function: Carries memory addresses from the CPU to other components, like RAM or
peripherals.
It determines the addressable memory space. For example, a 32-bit address bus can
address 4GB of memory.
The wider the address bus, the larger the range of memory addresses that can be
accessed.

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System buses
Control Bus −
Lines that carry control signals like clock signals, interrupt signal or ready
signal are called control bus. They are bidirectional.
Signal that denotes that a device is ready for processing is called ready signal.
Signal that indicates to a device to interrupt its process is called an interrupt
signal.

Function: Sends control signals to synchronize data transfers between the CPU
and other components.
Controls operations like read, write, interrupt, and halt.
Helps manage timing and ensures smooth data flow in a computer system.

Lecture 2: Hardware components of a Computers INTRODUCTION TO INFORMATION AND COMMUNICATION TECHNOLOGY ICT 32
Summary
This lecture covers:
◦ Components of a computer
◦ Input devices
◦ Output devices
◦ CPU and its components