Hardware The electric, electronic, and mechanical equipment that makes up a computer

INTRODUCTION TO COMPUTING.

(Computer Hardware: In Put and Output Devices ) Lecture # 04

By:

M.Nadeem Akhtar. Lecturer.

Department of CS & IT.

URL:

https://www.sites.google.com/site/uolcsitcf14fgh/home/lectures

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WHAT ARE HARDWARE AND SOFTWARE?

Hardware

The electric, electronic, and

mechanical equipment that

makes up a computer

Software

The series of instructions that tells the hardware

COMPUTER HARDWARE PARTS:

Computer System can be divided into main Three Parts/types:

1- In Put Devices 2- System Unit

3- Out Put Devices.

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THE COMPONENTS OF A

COMPUTER

What are common computer hardware components?

printer

scanner

speaker PC camera

microphone

digital camera

system unit

keyboard

modem

speaker

monitor

mouse

p. 1.5 Fig. 1-3

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p. 1.5 Fig. 1-3

THE COMPONENTS OF A

COMPUTER

What is an input device?

 Any hardware component that allows a user to enter

data and instructions into a computer

scanner microphone

keyboard

mouse PC camera

digital camera

Click to view Web Link

then click Input Devices 5

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p. 1.6 Fig. 1-3

THE COMPONENTS OF A

COMPUTER

What is an output device?

 Any hardware component that can convey information to a user

Click to view Web Link then click Output Devices

printer

monitor speakers

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THE COMPONENTS OF A

COMPUTER

What is the system unit ?

 Sometimes called a

chassis

 A box-like case made

from metal or plastic that protects the

internal electronic components of the computer from

damage

 Circuitry in the

system unit usually is part of or is connected to a circuit board

called the motherboard

p. 1.6 Fig. 1-3

CD-RW drive

CD-ROM or DVD-ROM drive

hard disk drive

floppy disk drive Zip®

disk drive

A keyboard is a set of typewriter like keys that

enables you to enter data into a computer

The keys on a computer keyboard are

classified as follow:

1. Alphanumeric keys (letters & numbers)

2. Punctuation keys (comma, semi colon etc…)

3. Special keys (function keys, control keys, arrow

keys etc..)

4. Toggle keys (keys that switches b/w two

different states like Num Lock, Caps Lock)

p. 5.4 Fig. 5-3

THE KEYBOARD

What is a keyboard?

 An input device that contains keys you press to enter data into

the computer

numeric keypad typing area

function keys

Click to view Web Link then click

Keyboards 10

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 The standard layout of letters, numbers &

punctuations is known as QWERTY keyboard

because the first six keys on the top row of letters is spelled as QWERTY.

 Another type is Dvorak Keyboard. It is designed so

that the middle row of the keys include the most common letters. It was designed for speed typing.

Keyboard

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QWERT vs Dvorak

 A desktop computer typically have 101 to 105 keys

containing alphanumeric, function & punctuation keys.

 Wireless keyboards battery powered device use radio

waves or infrared technology to transmit data.

Keyboard

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p. 5.4 Fig. 5-4

THE KEYBOARD

What are alternative forms for commands?

 Many programs allow you to use a button, a menu, or

a function key to obtain the same result

Command Button Menu Function Key(s)

Copy File|Copy SHIFT+F2

Open File|Open CTRL+F12

Print File|Print CTRL+SHIFT+F12

p. 5.6 Fig. 5-7

THE KEYBOARD

What is a portable keyboard?

 A full-sized

keyboard you

conveniently can attach and

remove from a handheld

computer

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A pointing device is an input device which is used to

control a pointer on a screen. Pointer is a small symbol on a screen.

 Mouse

 Trackball

 Joy Stick

 Touchpad

 And many more

Pointing Devices

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Click to view Web Link then click Mouse p. 5.7

MOUSE

What is a mouse?

 The most widely

used pointing

device on desktop computers

 Controls the

movement of the pointer, also called the mouse pointer, on the screen

Click to view video

MOUSE

How does a mechanical mouse work?

 A rubber or metal ball

is on its underside

 When the ball rolls in

a certain direction, electronic circuits in the mouse translate the movement of the mouse into signals the compute understands

p. 5.7 Fig. 5-9

mouse pad mouse pad ball ball wheel button wheel button mouse buttons mouse buttons

 _{A mouse pad}

provides better

traction and protects the ball from a build up of dust and dirt

p. 5.10 Fig. 5-13

OTHER POINTING DEVICES?

What is a trackball?

 A stationary

pointing

device with a ball on its

top

trackball

Click to view Web Link then click

Trackballs 18

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p. 5.10 Fig. 5-14

OTHER POINTING DEVICES

What is a touchpad?

 Also called a track pad

 A small flat,

rectangular

pointing device that is sensitive to pressure and motion

 Typically built

onto keyboards of laptop or

notebook

computers touchpad

Click to view Web Link then click Touchpads

p. 5.11 Fig. 5-15

OTHER POINTING DEVICES

What is a pointing stick?

 A

pressure-sensitive pointing device

shaped like a pencil

eraser that is positioned between

keys on the keyboard

pointing stick

Click to view Web Link then click Pointing Sticks

p. 5.11 Fig. 5-16

OTHER POINTING DEVICES

What are a joystick and a wheel?

 Help the user control the actions of players

and vehicles in game and simulation software

 A joystick is a vertical lever mounted on a

base

•

different directions to control the actions of a vehicle or

player

 A wheel is a steering-wheel type

of input device

•

•

joystick

pedal wheel

OTHER POINTING DEVICES

What is a light pen?

 A handheld input device that contains a light source or

can detect light

 Some require a

specially

designed monitor

 To select objects

on the screen, you press the

light pen against the surface of the screen and then press a button on the pen

p. 5.12 Fig. 5-18

OTHER POINTING DEVICES

What is a a touch screen?

 A touch-sensitive display

 You interact

with the device by touching

areas of the screen with your finger

 Often found in

kiosks located in stores,

hotels, airports

p. 5.13 Fig. 5-19

OTHER POINTING DEVICES

What is a stylus?

 Used in professional

graphical applications

 A graphics tablet, also

called a digitizer or

digitizing tablet, is a flat rectangular, electronic plastic board used with a stylus

 Looks like a ballpoint pen, but uses pressure to write

text and draw lines

 Originally called a pen or electronic penstylus or pen

Click to view Web Link then click Stylus

p. 5.13 Fig. 5-20

OTHER POINTING DEVICES

What is an electronic signature?

 Also called an e-signature

 Pen and graphics

tablet used with special software for handwriting recognition

 An electronic

signature is just as legal as an ink signature

Click to view Web Link

p. 5.16

VOICE INPUT

What is audio input?

 The process of entering any sound into the computer

such a s speech, music, and sound effects

 Requires a sound card

 Input sound via a device such as a microphone, tape

player, CD player, or radio each of which plugs into a port on sound card.

 Windows stores audio files as waveforms

 Called WAV files with a .wav extension

p. 5.16 Fig. 5-23

VOICE INPUT

What is MIDI( Musical Instrument Digital Interface)?

 An external device such as an electronic piano keyboard

used to input music and other sound effects

 Music is stored in the computer

p. 5.21 Fig. 5-29

VIDEO INPUT

What is video input?

 The process of entering a full-motion recoding into a computer and

storing it on a storage medium

analog video camera analog video

camera

video-in plug video-in

plug

digital video camera digital video

camera

video digitizer Used to capture

an individual frame from an analog video and

then save the picture in a file

p. 5.21

VIDEO INPUT

What are some factors related to video input?

 Video files can require huge amounts of storage space

 Video compression is used to decrease the size of the files  Files can be compressed using software or hardware

video decoder A card that decompresses

video data

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p. 5.22 Fig. 5-30

VIDEO INPUT

What is a PC video camera?

 A DV camera that allows the home user to record, edit,

and capture video and still images and to make video telephone calls on the Internet

 Also called a PC camera

PC video camera

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p. 5.23 Fig. 5-31

VIDEO INPUT

What is a Web cam?

 A video camera whose output displays on a Web page

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p. 5.24 Fig. 5-32

VIDEO INPUT

What is videoconferencing?

 A meeting between two or more geographically separated

people who use a network on the Internet to transmit audio an video data

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p. 5.24

SCANNERS AND READING DEVICES

What is a scanner?

 A device that captures data directly from source

documents

 A source document is the original form of the data

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p. 5.25 Fig. 5-34

SCANNERS AND READING DEVICES

What is an optical scanner?

 Usually called a scanner

 A light-sensing input device that reads printed text

and graphics and then translates the results into a form the computer can use

 A flatbed scanner,

a more popular type, works

similarly to a copy machine except it creates a file of the document in memory instead of a paper copy

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p. 5.26 Fig. 5-34

SCANNERS AND READING DEVICES

What are various types of scanners?

Click to view Web Link then click Scanners

Pen or handheld

Drum

Sheet-fed

Flatbed

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p. 5.27

SCANNERS AND READING DEVICES

What is an optical reader?

 A device that uses a light source to read characters, marks

and codes and then converts them into digital data that a computer can process

Optical character recognition (OCR)

Optical mark recognition

Bar code scanner

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p. 5.30 Fig. 5-41

SCANNERS AND READING DEVICES

What is a magnetic Ink character recognition reader (MICR)?

 Can read text printed with magnetized ink

 The banking industry almost exclusively uses MICR

for check processing

check number

bank number

check amount account

number

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• Any hardware component used to show results

after processing to any user. Output can be text, Audio, Video & graphics.

• Examples

 Display device

• Monitor • Printer • Plotter

• Projectors

• Speakers

• Headphone etc

2. OUTPUT DEVICES

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A display device is simply an output device that visually conveys text, graphics & video information.

Information on a display device, sometimes

called soft copy exists for a temporary period only.

Display devices include:

 CRT Monitors

 LCD Monitors

 Gas Plasma Monitors

 Televisions

Monitors

Display Devices

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 Similar to standard Television because it contains the CRT (Cathode Ray Tube)

 CRT is a large, sealed, glass tube

 The front of the tube is screen

 Tiny dots of phosphorus material coat the screen

 Each dot consists of red, green & blue phosphorus.



 The actual viewable area is however, less than the diagonal size. For example, a 21 inches monitor will have 19.8 inches viewable area

Inside CRT, an electronic beam moves back & forth across the back site of the screen which causes the dots on the front of the screen to glow Three dots combine to make up one pixel

 The size of CRT monitors can be 14, 15, 17, 19, 21 and 22 plus more inches which is measured diagonally.

CRT Monitors

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 LCD Monitors use Liquid Crystal

 LCD contains liquid crystals between two sheets of material

 When an electric current passes through the crystals, they twist which causes the image to be displayed on the screen

 LCD Monitors are the type of the flat-panel displays

 Flat Panel displays have less weight, compact screen & consume less than one third the power consumed by CRT monitors

 The size ranges from 15, 17, 18, 20 and 21 plus more inches

 LCD Monitors typically are more expensive than CRT Monitors

 Desktop, Notebook & Handheld computers often use LCD displays

LCD or TFT:

Active Matrix or Thin Film Transistor (TFT) Display: Higher refresh rate & contrast

LCD Monitors

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 Gas Plasma Monitors are Flat-Panel screens instead only they use gas plasma technology, which substitutes a

layer

of gas for the liquid crystal material in an LCD monitor

 When voltage is applied, the gas released UV light.

 The UV light causes the pixels on the screen to glow

 _{The Gas Plasma Monitors can be more than 42” wide.}

 Refresh Rate: Phosphorus on the CRT Monitors must be refreshed 50 to 100 times after every second (Hz).

 Faster refresh rate causes fewer flickers on screen

 Monitor Resolution: Depends upon the number of bits to be used to display each pixel:

 28 _{bits = 256 colors}

 216 _{bits = 65536 colors}

 224 _{to 2}32 _{bits = 16 million to 4 billion colors}

Gas Plasma Monitors

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A printer is an output device that produces text and graphics on a physical medium such as paper or transparency film.

Printed information is called hard copy. And is more permanent than a soft copy.

There are two types of printers:

1. Impact Printers

2. Non-Impact Printers

An impact printer forms characters and graphics on a piece of paper by striking a mechanism against an inked ribbon that physically contacts the paper.

 Impact printers are noisy because of this striking activity.

 Impact printers normally do not provide Letter Quality (LQ) printing. They are ideal to print multipart forms because they easily can print through many layers of papers.

Printers

Impact Printers

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Two commonly used types of impact printers are:

a. Dot Matrix Printers b. Line Printers

Dot Matrix Printers

Dot Matrix Printer produces the printed images when tiny wire pins on a print Head mechanism strike an inked ribbon.

When ribbon passes against the paper, it creates dots that form characters and graphics.

The print head can contain 9 to 24 pins. A high number of pins means the printer prints more dots per character, which results in higher print quality.

Printers

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Most dot matrix printers use continuous-form paper, in which each sheet of paper is connected together. The pages have holes along the sides to help feed the paper.

The speed is measured by number of characters per second (CPS). It ranges from 300 to 1100 CPS

Factories & retail counters use impact printers because these printers can withstand dusty environment, vibrations & extreme temperatures.

9-pin dot matrix printer in action

Printers (a-

Dot Matrix Printers )

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B-Line Printers

• A line printer is a high speed impact printer that prints an entire line a time.

• The speed is measured by number of lines it can print. (LPM). These printers are capable to print 3000 LPM.

•A line printer is often connected with a midrange mainframe, server or network.

•Line printers are bigger in size & are more expensive than dot matrix printers.

Printers

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•A non-impact printer forms characters & graphics on a piece of paper without actually striking the paper.

• Some spray ink, while others use heat & pressure to create images. Because, these printers do not strike the paper, they are much quieter than impact

printers.

The commonly used types of the non-impact printers are:

 Ink-jet printers

 Laser Printers

2-Non-impact Printer

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Ink Jet Printers create characters & graphics by spraying tiny drops of liquid ink onto a piece of paper.

•Ink Jet Printers usually use individual sheets of paper stored in removable or stationary tray.

• These printers can print both black & white & color prints on a variety of paper types. e.g., plain papers, photo paper, glossy paper and banner paper.

• Most Ink Jet Printers have the resolution ranges from 300 to 2400 dpi & speed 3 to 20 p p m.

Higher the dpi, better the quality of the image

Ink Jet Printers have become most popular type of the color printers especially in homes because of their lower cost & better quality printing

Ink-Jet Printers

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Laser Printers use a laser to mark the parts of the page where the text & image is to formed. The paper is passed through a toner solution where the mark areas pick up the toner & the text becomes visible.

Laser Printers usually use individual sheets of paper

stored in removable or stationary tray. Some laser printers have trays that can accommodate different sizes of papers.

These Printers can print both black, white & gray and color prints. However, color laser printers are expensive.

Most Laser Printers have the resolution ranges from 600 to 2400 dpi & speed 6 to 40 ppm.

HP Laser Jet 2100

HP Color Laser Jet 4550

Laser Printers

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DISPLAY DEVICES

What is a Web-enabled device?

 A device that allows

access to the Web or e-mail such as cellular telephones and pagers

 Uses an LCD display

 Many use

monochrome displays to save battery power

Click to view Web Link then click

Web-enabled Devices

p. 6.6 Fig. 6-6

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DISPLAY DEVICES

What is an electronic book (e-book)?

 A small, book-sized computer that uses an LCD screen

 Allows users to read, save, highlight, bookmark, and add notes to

online text

 Download new book content from the Web

Clear Type, a new technology developed

by Microsoft, used to

improve the quality of

reading material on LCD screens

p. 6.7 Fig. 6-7

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800 x 600 typically the

standard

DISPLAY DEVICES

What is display resolution?

 Describes the sharpness and clearness of an image

 Resolution of a display device stated as dots, or pixels

1280 x 1024

maximum resolution of most monitors

800 horizontal

pixels

600 vertical pixels

Total of 480,000 pixels on screen

OTHER OUTPUT DEVICES

What is a data projector?

 A device that takes the image from a computer screen

and projects it onto a larger screen so an audience of people can see the image clearly

p. 6.25 Fig. 6-32

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special-purpose terminals intelligent

terminals

TERMINALS

What is a terminal?

 A device that performs both input and output because it

consists of a monitor (output), a keyboard (input), and a video card

 Three basic categories

dumb terminals

p. 6.27

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TERMINALS

What is a dumb terminal?

 Has no processing power so it cannot function as an

independent device

 Can enter and transmit

data to, or receive and display information from, a computer to which it is connected

 Connect to a host

computer that performs the processing and then sends the output back to the dumb terminal

p. 6.27 Fig. 6-36

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TERMINALS

What is an intelligent terminal?

 Has memory and a

processor that has the capability of performing some functions

independent of the host computer

 Sometimes called

programmable

terminals because they can be

programmed by the software developer to perform basic tasks

p. 6.28

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TERMINALS

What is a point-of-sale (POS) terminal?

 Records purchases at the

point where the consumer purchases a product or a service

 Output from POS terminals

serve as input to other

computers to maintain sales records, update inventory, verify credit, and perform other activities associated with the sales transactions that are critical to running the business

POS terminal

Click to view Web Link then click POS Terminals

p. 6.28 Fig. 6-37

TERMINALS

What is an automated teller machine (ATM)?

 A self-service banking

machine that connects to a host computer through a telephone network

 Insert a plastic bankcard

with a magnetic strip into the ATM

 Enter your password,

called a personal

identification number

(PIN), to access your bank account

Click to view Web Link then click Automated Teller Machines

Click to view video

p. 6.29 Fig. 6-37