IT 111 Information Technology Fundamentals

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OUTPUT and its DEVICES

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CONTENTS

• Introduction

• Output Types

• Output Devices

Monitors

Printers

Introduction

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Output is data that has been processed into a useful form.

Output is an optional step in the information processing cycle but may be ordered by the user or program.

The computer may be required to display the results of its processing.

The results may appear as text, numbers, or a graphic on the computer’s screen or as sounds from its speaker.

The computer also can send output to a printer or transfer the output to another computer through a network or the internet.

Output Types

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1. Text output

-Textual information

2. Graphics output

-Visual images - photos,

diagrams, icons

3. Video output

-Moving images

4. Audio output

Sounds - music, voice,

podcasts

TEXT

AUDIO

Output Devices

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Output devices are peripheral devices that enable us to view

or hear the computer’s processed data.

Commonly used Output Devices

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1. Monitors/Display devices

2. Printers

3. Speakers

4. Headphones and earbuds

5. Data Projectors

6. Interactive whiteboards

7. Force-feedback game controllers

8. Tactile output

1. Monitors

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A peripheral device which displays computer output on a

screen.

Screen output is referred to as soft copy.

It is the most commonly used output device on personal

computer systems

Two important hardware devices determine the quality of

the image you see on any monitor:

1. monitor itself

2. video controller

Types of monitors

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Cathode-ray tube (CRT)

Liquid Crystal Display (LCD or flat-panel)

CRT LCD

Types of monitors

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CRT- Cathode Ray Tube Uses a large vacuum tube sealed glass tube.

electron gun shoots a stream of electrons at a

specially phosphor-coated screen

on impact, the phosphor flares up for a fraction of a second

electron gun sweeps across the screen many times a second(R to L then Top to bottom then refreshes screen in a diagonal manner)

Have been the standard for use with desktop computers because they provide a bright, clear picture at a relatively low cost.

Disadvantages of CRT monitors

They take up desktop space and can be difficult to move.

Requires a lot of power to run

The CRT electron gun

“shoots” 3 electrons at

the screen representing

the amount of red,

green and blue for the

pixel

CRT- Cathode Ray Tube

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Common screen sizes are 15, 17,

19,21, and 22 inches.

A CRT monitor's viewable size is the

diagonal measurement of the actual

viewing area.

A 21-inch monitor have a viewable

size of 20 inches.

The popularity of CRT monitors

is declining

Types of monitors

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LCD -Liquid Crystal Display one of several types of “flat-panel” displays contain fluorescent tubes that emit light waves to liquid-crystal cells, sandwiched between two

sheets of material When an electrical charge passes through the

cells, the cells twist, causing some light waves to be blocked and allows others to pass through, creating images on the display

forms output by solidifying liquid crystals and “backlighting” the image with a light source

Disadvantages Images can be difficult to see in bright light Limited viewing angle

Main categories of LCD

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Passive matrix LCD relies on transistors to form a grid that define location of each

pixel the color displayed by a pixel is determined by electricity at the

end of the row and at the top of the column DISADVANTAGE – refresh rate is slow; limited viewing angle proof is when you move the pointer too quickly, it

disappears(effect known as submarining); animated graphics is blurry on this type

Active matrix LCD assigns a transistors to each pixel each pixel is turned on and off individually allowing rapid refresh

rate Wider viewing angle through TFT(Thin Film Transistor)

technology which employs four transistors per pixel another TFTcalled organic LED (OLED), uses organic molecules

that produce an even brighter, easier-to-read display

Other Types of Monitors

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1. Paper-white displays Sometimes used by document designers such as desktop publishing

specialists, newspaper or magazine compositors, and other persons who create high quality printed documents.

Produces a very high contrast between the monitor’s white background and displayed text or graphics, which usually appear in black.

2. Electroluminescent displays (ELDs) Similar to LCD monitors but use a phosphorescent film held

between two sheets of glass. A grid of wires sends current through the film to create an image

3. Plasma displays Are created by sandwiching a special gas (such as neon or xenon)

between two sheets of glass. When gas is electrified, it glows projecting the image.

Screen sizes up to 150 inches wide, richer colors, more expensive, hang directly on a wall.

Plasma display

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Categories of monitor by the way they display colors

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1. Monochrome Display only one color (such as green, amber, or white)

against a contrasting background, which is usually black. Used for text-only displays where the user does not need to

see color graphics

2. Grayscale Display varying intensities of gray (from a very light gray to black)

against a white or off-white background Used in low-end portable systems , especially handheld computers to keep costs down

3. Color Can display between 16 colors and 16 million colors. Most new monitors display in color. Many color monitors can be set to

work in monochrome or grayscale mode.

Comparing Monitors

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1. Size Affects how well you can see images. Are measured diagonally, in inches, across the front of the

screen. As a rule of thumb, buy the largest monitor you can afford. Typical Display Sizes sizes of LCD monitors are, 17,19,20,22,24,26,27inches;

some are 45 or 65 inches; most are widescreen, Notebooks’ typical sizes of 14.1, 15.4, 17, and 20.1 inches. Tablet PC screens range from 8.4 inches to 14.1 inches. Ultra-Mobile PCs are 5 inches to 7 inches. Portable media players from 1.5 inches to 3.5 inches. Smartphones from 2.5 inches to 4.1 inches. Digital camera range from 2.5 inches to 4 inches.

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2. Resolution Determined by the number of pixels on the screen, a matrix. The more pixels a monitor can display, the higher its resolution

and the clearer and sharper its images appear As the resolution increases, the image on the screen gets smaller. Higher settings are not always better, they can cause objects on

the screen to appear too small, resulting in eyestrain and squinting.

For example, a monitor that has a 1440 X 900 resolution displays up to 1440 pixels per row and 900 pixels per column, for a total of 1,296,000 pixels to create a screen image.

Resulting to better sharpness or clarity of an image. A recent study has shown that out of 6 million users surveyed,

nearly one-half use a 1024 X 768 screen resolution.

Comparing Monitors

Resolution

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With LCD screens, a widescreen 19-inch LCD monitor typically has a

resolution of 1440 X 900, while a widescreen 22-inch has a resolution

of 1680 X 1050.

LCDs are set to a specific resolution, called the native resolution.

To change screen resolution,

1. right-click the desktop,

2. click Personalize on the shortcut menu,

3. click the Display Settings link,

4. make desired changes in the Display Settings dialog

box

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3. Refresh rate

Number of times per second that the electron guns scan every

pixel on the screen.

If the screen is not refreshed often enough, it appears to

flicker, and flicker is one of the main causes of eyestrain.

Refresh rate is measured in Hertz (Hz), or in cycles per second

If a monitor’s refresh rate is 100 Hz, it refreshes its pixels 100

times every second.

Sometimes referred to as Response time

Comparing Monitors

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4. Dot pitch sometimes called pixel pitch

The distance between the like-colored phosphor dots of

adjacent pixels.

Is measured as a fraction of a millimeter (mm), and dot pitches

can range from .15 mm (very fine) to .40 mm or higher.

Average dot pitch on LCD monitors and screens should be .30

mm or lower.

The smaller the dot pitch, the finer and more detailed images

will appear on the monitor.

Text created with a smaller dot pitch is easier to read.

Advertisements normally specify a monitor's dot pitch or pixel

pitch.

Comparing Monitors

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5. Brightness measured in nits.

a nit is a unit of visible light intensity equal to one candela

(formerly called candlepower) per square meter.

the candela is the standard unit of luminous intensity.

LCD monitors and screens today range from 250 to 550 nits.

the higher the nits, the brighter the images.

6. Contrast ratio describes the difference in light intensity between the brightest

white and darkest black that can be displayed.

Contrast ratios today range from 500:1 to 2000:1.

Higher contrast ratios represent colors better.

Comparing Monitors

Standards

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The aspect ratio defines a display's width relative to its

height.

A 2:1 aspect ratio, for example, means the display is

twice as wide as it is tall.

The aspect ratio for widescreen monitors is 16:lO.

Some display devices support multiple video standards.

Comparing Monitors

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SVGA Super Video Graphics Array 800 x 600 4:3

XGA Extended Graphics Array 1024 x 768 4:3

SXGA Super XGA 1280 x 1024 5:4

WXGA Wide XGA 1280 x 1024 16:9

or 1366 x 768 16:10

UXGA Ultra XGA 1600 x 1200 4:3

WSXGA Wide Super XGA 1680 x 1050 16:10

WUXGA Wide Ultra XGA 1920 x 1200 16:10

WQXGA Wide Quad XGA 2560 x 1600 16:10

Wide (widescreen) video standard formats are preferable for

users who watch movies and play video games on the

computer.

Video cards

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Also called the video controller or the video adapter

Is an intermediary device between the CPU and the monitor.

It contains the video-dedicated memory and other circuitry necessary to send information to the monitor

for display on the screen.

To display the highest quality images, an LCD monitor should plug in

a DVI port, an HDMI port, or a DisplayPort.

A DVI (Digital Video Interface) port enables digital signals to

transmit directly to the LCD monitor.

An HDMI (High-Definition Media Interface) port combines

DVI with high-definition(HD) television and video.

The DisplayPort is an alternative to DVI that also supports HDMI.

standard monitor port

Video Display Terminology

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Pixel picture element (smallest unit of an image, basically a

single dot on the screen)

Resolution number of pixels in the image

Common resolution size is 1024x768

Refresh rate how often a CRT’s electron gun rescans

LCD displays do not use an electron gun, so do not perform refreshing

2. Printers

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A printer is a peripheral

device that produces a

physical copy or hard copy

of the computer’s output.

Non-Impact Printers

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A nonimpact printer forms characters and

graphics on a piece of paper without actually

striking the paper.

Some spray ink, while others use heat or pressure to create

images.

Commonly used nonimpact printers are:

ink-jet printers, photo printers, laser printers,

thermal printers, mobile printers, label and

postage printers, plotters, and large-format

printers.

Types of Non-Impact Printers

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Inkjet printer, also called a

bubble-jet, makes characters

by inserting dots of ink onto

paper

Letter-quality printouts

Cost of printer is inexpensive

but ink is costly

Laser printer works like a

copier

Quality determined by dots

per inch (dpi) produced

Color printers available

Expensive initial costs but

cheaper to operate per page

Inkjet Laser

Ink Jet Printer

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Create an image directly on the paper

by spraying ink through tiny nozzles.

The only part that needs routine replacement is the ink cartridge.

The print head mechanism in an ink-jet printer contains ink-filled

cartridges. Each cartridge has fifty to several hundred small ink

holes or nozzles.

uses two or more ink cartridges: one containing black ink and the

other(s) containing colors.

Cartridges with black ink cost $15 to $30 each.

Color ink cartridge prices range from $20 to $35 each.

black ink cartridges typically print from 200 to 800 pages, and

color ink cartridges from 125 to 450 pages.

Ink Jet Printer

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-pages per minute (ppm) it can print is from 12 to 36 ppm

Most ink-jet printers can print from 1200 to 4800 dpi.

the higher the dpi, the better the print quality. The

difference in quality becomes noticeable when the size

of the printed image increases.

Ink Jet Printer

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Ink-jet printers also print on other materials such as envelopes,

labels, index cards, greeting card paper (card stock),

transparencies, and iron-on T-shirt transfers.

Many ink-jet printers include software for creating greeting

cards, banners, business cards, and letterhead.

Most ink-jet printers can print from 1200 to 4800 dpi.

Ink-jet printers are a popular type of color printer used in the

home.

Laser Printer

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More expensive, faster, lower cost per page

Uses technology similar to that in photocopiers.

Toner – composed of tiny particles of ink, sticks to the drum

in the places the laser has charged.

Toner cartridge prices range from $50 to $170 for about

5,000 printed pages.

print in usually 1200 dpi for black-and-white printers and up

to 2400 dpi for color printers.

a laser printer for the small business user can have up to 768

MB of memory and a 40 GB hard disk.

- To print a full-page 1200-dpi photo, you need 64 MB of

memory in the printer.

Laser Printer

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a laser printer for the small business user can have up to 768 MB of

memory and a 40 GB hard disk.

use software to interpret a page description language (PDL)

tells the printer how to arrange the contents of a printed page.

two common page description languages: PCL or PostScript.

Developed by HP, a leading printer manufacturer

PCL (Printer Control-Language) is a standard

printer language that supports the fonts and layout used in standard office

documents.

Professionals in the desktop publishing and graphic art fields commonly use

PostScript because it is designed for complex documents with intense graphics

and colors.

How a Black-and-White Laser Printer Works

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Step 1

After the user sends an

instruction to print a

document, the drum rotates

as gears and rollers feed a

sheet of paper into the printer.

Step 3

The laser beam creates a

charge that causes toner to

stick to the drum.

Step 5

As the drum continues to

rotate and press against

the paper, the toner transfers

from the drum to the paper.

Step 2

A rotating mirror deflects a low-

powered

laser beam across the surface of a

drum.

Step 4

A set of rollers uses

heat and pressure to

fuse the toner

permanently to the paper.

Impact Printers

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An impact printer forms characters and graphics on paper by striking a

mechanism against an inked ribbon that physically contacts the paper.

noisy because of this striking activity.

produce near letter quality (NLQ) output, a print quality less acceptable for

business letters.

Companies use them for routine jobs like printing labels, multipart forms

because they easily print through layers of paper.

Factories, warehouses, and retail counters use them because these printers

withstand dusty environments, vibrations, and extreme temperatures.

Two commonly used types of impact printers are dot-matrix printers and

line printers.

Dot Matrix Printers

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Commonly used in workplaces

where physical impact with the

paper is important, such as when the

user is printing to carbon copy or

pressure sensitive forms.

Can produce sheets of plain text

very quickly.

Speed is measured in characters per

second (cps).

A dot-matrix printer produces

printed images when tiny pins

strike an inked

ribbon.

Line & Band Printers

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Line Printer

Works like a dot matrix printer but uses a special wide print head that can

print an entire line of text at one time.

Do not offer high resolution but are incredibly fast.

Band Printers

Feature a rotating band embossed with alphanumeric characters.

To print a character, the machine rotates the band to the desired character,

then a small hammer taps the band pressing the character against a ribbon.

Very fast and very robust

Comparing Printers

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1. Image Quality

Also known as print resolution

Usually measured in dots per inch (dpi)

The more dots per inch a printer can produce, the higher its image quality.

2. Speed

Measured in the number of pages per minute (ppm) the device can print

Most printers have different ppm ratings for text and graphics because

graphics generally take longer to print.

3. Initial Cost

The cost of new printers has fallen dramatically in recent years, while their

capabilities and speed have improved just as dramatically.

4. Cost of Operation

The cost of ink or toner and maintenance varies with the type of printer.

Many different types of printer paper are available too and the choice can

affect the cost of operation.

High-Quality Printers

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1. Photo Printers Work slowly; some can take two or four

minutes to create a printout. Advantage: PictBridge enabled--can

print photos without a computer. PictBridge - a standard technology that

allows you to print photos directly from a digital camera by connecting a cable from the digital camera to a USB port on the printer or by an infrared connection.

Many photo printers use ink-jet technology.

Printer prints photos in camera when camera sits in docking station.

High-Quality Printers

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2. Thermal-Wax Printers Used primary for presentation graphics and

handouts. Create bold colors and have a low per-page

cost for printouts with heavy color requirements, such as posters or book covers

Operate with a ribbon coated with panels of colored wax that melts and adheres to plain paper as colored dots when passed over a focused heat source.

Printing plastic labels for chemical containers (because the cheaper types of plastic would melt in a laser printer)

High-Quality Printers

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3. Dye-Sublimation Printers sometimes called a digital photo printer, uses heat to transfer

colored dye to specially coated paper. create images that are of photographic quality Used in Professional applications requiring high image

quality, such as photography studios, medical labs, and security identification systems

These high-end printers cost thousands of dollars and print images in a wide range of sizes.

High-Quality Printers

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4. Plotters

A plotter is a printer that uses a pen that moves over a large

revolving sheet of paper.

It is used in engineering, drafting, map making, and

seismology.

Large format printers

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Label Printers

All-in-One Printers

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Combine printing capabilities with scanning, photocopying, and

faxing capabilities.

Small, lightweight, and easy to use.

Audio Output: Sound Cards and

Speakers

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Audio output is the ability of the computer to output sound.

Two components are needed:

Sound card – Plays contents of digitized

recordings

Speakers – Attach to sound card

Data Projectors

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Data Projectors

Also called digital light projectors and video projectors

1. LCD Projectors - Liquid Crystal Display

– require the room to be darkened. They display blurry images in less-

than-optimal lighting conditions.

2. DLP Projectors - Digital Light Processing

– project brighter, crisper images. Can display clear images in normal

lighting conditions.