Ch4 output devices

Chapter 4AChapter 4A

Video and Sound

1

MonitorsMonitorsMost common output deviceConnects to the video cardCategorized by color output

◦Monochrome One color with black background

◦Grayscale Varying degrees of gray

◦Color Display 4 to 16 million colors

2

MonitorsMonitors

1. Cathode Ray Tube (CRT)◦Most common type of monitor◦Electrons fired from the back◦Electrons excite phosphor to glow◦Phosphor is arranged in dots called

pixels◦Dot mask ensures proper pixel is lit

3

MonitorsMonitorsCRT color

◦Phosphor dots arranged in triads◦Red, green, and blue dots◦Three colors blend to make colors◦Varying the intensity creates new

colors

4

MonitorsMonitorsCRT drawbacks

◦Very large ◦Very heavy◦Use a lot of electricity

5

MonitorsMonitors

2. Liquid Crystal Display (LCD)◦Commonly found on laptops◦Desktop versions exist◦Solve the problems of CRT◦Fluorescent lights provide

illumination

6

MonitorsMonitorsDrawbacks to LCD

◦More expensive than CRT◦Must sit directly in front of screen◦Can be more fragile than CRT

7

MonitorsMonitors

3. Plasma monitor◦Gas is excited to produce light

8

Monitors and Video CardsMonitors and Video CardsComparing Monitors:

1. Size2. Resolution3. Refresh rate4. Dot pitch

9

Monitors and Video CardsMonitors and Video Cards

1. Size of monitor◦Measured in inches◦Actual size

Distance from corner to corner

◦Viewable size Useable portion of the screen

10

Monitors and Video CardsMonitors and Video Cards

2. Resolution◦Number of pixels on the screen◦Higher number creates sharper

images◦Higher number creates smaller

images

11

Monitors and Video CardsMonitors and Video Cards

3. Refresh rate◦Number of time the screen is redrawn◦Modern equipment sets this

automatically◦Improper settings can cause eyestrain

4. Dot pitch◦Distance between the same color dots

12

Video CardsVideo CardsDevice between the CPU and monitorBetter cards result in better outputRemoves burden of drawing from

CPUHave their own processor and RAMModern cards have up to 512 MB

RAMCapable of rendering 3D images

13

Data ProjectorsData ProjectorsReplaced overhead and slide

projectorsProject image onto wall or screenLCD projectors

◦Most common type of projector◦Small LCD screen◦Very bright light◦Require a darkened room

14

Data ProjectorsData ProjectorsDigital Light Projectors

◦A series of mirrors control the display◦May be used in a lighted room

15

Sound SystemsSound Systems• Integral part of the computer

experienceCapable of recording and

playback

16

Sound SystemsSound SystemsSound card

◦Device between the CPU and speakers

◦Converts digital sounds to analog◦Can be connected to several devices

17

Sound SystemsSound SystemsHeadphones and headsets

◦Replacement for speakers and microphones

◦Offer privacy◦Does not annoy other people◦Outside noise is not a factor◦Headsets have speakers and a

microphone

18

Chapter 4BChapter 4B

Printing

19

Commonly Used PrintersCommonly Used PrintersImpact printers

◦Generate output by striking the paper

◦Uses an inked ribbon Non-impact printers

◦Use methods other than force◦Tend to be quiet and fast

20

Commonly Used PrintersCommonly Used Printers

1. Dot matrix printers◦Impact printer◦Used to print to multi-sheet pages◦Line printers◦Band printers◦Speed measured in characters per

second

21

Dot Matrix Print HeadDot Matrix Print Head

22

Commonly Used PrintersCommonly Used Printers

2. Ink-jet printers◦Non-impact printer◦Inexpensive home printer◦Color output common using CMYK

Cyan, magenta, yellow, black

◦Sprays ink onto paper◦Speed measured in pages per

minute◦Quality expressed as dots per inch

23

Dots Per InchDots Per Inch

24

Commonly Used PrintersCommonly Used Printers

3. Laser printer◦Non-impact printer◦Produces high quality documents◦Color or black and white◦Speed measured in pages per

minute◦Quality expressed as dots per inch

25

Commonly Used PrintersCommonly Used Printers

4. All-in-one peripherals◦Scanner, copier, printer and fax◦Popular in home offices◦Prices are very reasonable

26

Comparing PrintersComparing PrintersDetermine what you needDetermine what you can spendInitial costCost of operatingImage qualitySpeed

27

High-Quality PrintersHigh-Quality Printers

1. Special purpose printers◦Used by a print shop◦Output is professional grade◦Prints to a variety of surfaces

28

High-Quality PrintersHigh-Quality Printers

2. Photo printers◦Produces film quality pictures◦Prints very slow◦Prints a variety of sizes

29

High-Quality PrintersHigh-Quality Printers

3. Thermal wax printers◦Produces bold color output◦Color generated by melting wax◦Colors do not bleed ◦Operation costs are low◦Output is slow

30

High-Quality PrintersHigh-Quality Printers

4. Dye sublimation printers◦Produces realistic output◦Very high quality◦Color is produced by evaporating ink◦Operation costs are high◦Output is very slow

31

High-Quality PrintersHigh-Quality Printers

5. Plotters◦Large high quality blueprints◦Older models draw with pens◦Operational costs are low◦Output is very slow

32

Chapter 4Chapter 4

End of Chapter

33