Chapter 2 – Coputer Hardware

Computer Components - Hardware

Lecture 2

Outline

Computer Components Hardware Components Central Processing Unit Input Units Output Units Memory Unit Storage Units

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Computer Components

Computers have two main components:

Hardware

Physical components like screen and keyboard

Software

Set of instructions that tells the computer what to do and how to do it

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Hardware Components

Central Processing Unit

Input Units

Output Units

Memory Unit

Storage Units

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Hardware Components

Input Units

Output Units

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Control Unit

Storage Unit

ALU Unit

Hardware Components

Input Units

Output Units

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Control Unit

Storage Unit

ALU Unit

Central Processing Unit (CPU)

Every PC system unit contains at least one chip called microprocessor (CPU) attached on motherboard.

The CPU follow the instructions to process the data to produce the information

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Central Processing Unit (CPU)

Its is the brain of Computer.

It interprets and executes the instruction contained in software program.

It determines how fast your computer will run .

Its speed measured in MHz/GHz ( Megahertz or Gigahertz )

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Central Processing Unit (CPU)

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CPU Compone

nts

Control Unit(CU)

Arithmetic Logic Unit

(ALU)Registers

Central Processing Unit (CPU)

Control Unit (CU)

tells the rest of the computer system how to carry out the program’s instructions .

it moves the electronic signals (data) between :

Main memory and Arithmetic unit.

Main memory and Input/ output devices

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Central Processing Unit (CPU) Arithmetic and Logic Unit (ALU)

It performs mathematical and logical operations.

arithmetic (a= 5+4)

Logic (a > b) Registers

Are immediate memory location used by the

ALU to store the data in execution.

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Hardware Components

Input Units

Output Units

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Control Unit

Storage Unit

ALU Unit

Input Units

Input devices: are hardware used to translate data (words, sounds, images) into a form that the computer can process .

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Input Units

Input Units

Keyboard

Mouse

Trackball

Touch Pad

Input Units

Scanner

Bar Code

Reader

Joy Stick

Touch Pad 14

Input Units

OMR

Microphone

Magnetic Strip

Light Pen

Input Units

Keyboard

It is a board containing the keys of letters, numbers and some functions which allows you to type information into the computer.

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Input Units

The Mouse

A small hand-held device used to point, select, click on items and to drag and drop items from one place to another.

Trackball : it is a mouse turned upside down.

The user rotate the ball with the fingers to move the cursor on the screen, and it saves the space which is taken up by the mouse

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Input Units Touch pad It is touch – sensitive device. We can move the cursor by

move the finger on the pad surface (used in laptops).

Light pen It is a light sensitive device, or pen-

like device, connected to the computer by wire .

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Input Units

Scanner

It allows you to scan pictures, text and images and save it to your computer in a digital form.

The Scanners can read the bar codes.

Scanner Types Next slide

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FlatBad

Sheet Fed

handHeld

Stationary Scanner

Drum Scanner

Input Units

Bar Code Reader

It is a Photoelectric scanner that translates the bar code symbols into digital form.

Joystick

Small hand-lever that can be moved in any directions to control movement on the screen. It can be used for playing games

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Input Units

Optical Mark Reader (OMR): is a device reads pencil marks on compatible scan form

Ex: Answer forms.

Magnetic Strip

A Thin Layer of magnetic material which is placed on credit cards and bank ATM cards and hotel room keys.

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Input Units

Microphone : used o record the sound on the computer or input spoken text into the word

processor.

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Input Units

Digital camera : the same as traditional camera but use the flash or disk to save images.

Video Camera: connected to the computer to be used in video conferencing or store movies.

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Hardware Components

Input Units

Output Units

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Control Unit

Storage Unit

ALU Unit

Output Units

Output devices: Devices used to translate the processed information into a form that humans can understand.

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Output Units

Output Units

Speakers

Projector Plotters Printers Monitor

s

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Output Units

Monitors (Computer Screens )

It displays the text, information and pictures.

They are different in sizes, resolution and color.

Types of monitors:

1- Cathode Ray Tube (CRT)

2- Flat-Panel Display

Technologies include : liquid crystal display (LCD), plasma displays.

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Output Units

Printers

-It is used to print the information or output of computers on papers.

Printer Type

1- Daisy wheel

characters are raised on the wheel , which strike the ribbon placed between them and the paper. (noisy and slow and produce carbon copies)

2-Dot matrix

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Output Units

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2-Dot matrix use the pins to strike on an inked ribbon against paper. (inexpensive, produce carbon copies) 3-Inkjet

spray one or more colors of small droplets of ink at high speed onto paper. and its running cost is high.

(carbon copies can’t be produced).

(use one color or multiple colors)

Output Units

4-Laser printer

use a laser beam source to create a dot-like images on a drum. And these image treated magnetically charged ink-like toner and transferred from drum to paper.

(high quality, used for heavy use, expensive, can’t produce carbon copies)

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Output Units (3-Plotters)

Plotters

A special Printer use pen to draw on the paper under the computer control and the mapping software (used to draw maps).

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Output Units

Speaker/Head phones

They are used to output voice from a computer.

Projectors

Device that connect to computer to display output to large board

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Input & Output Devices

Touch Screen

A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area.

It can be used as both Input and output device at the same time,

receives input from a finger or pin, and displays output on the screen.

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