Output
Software brings the machine to Life
System Software
Application Software
Computer Data
Computer Users
The User’s Role
Userless Computers Output
Text, Graphics, Audio, Video
Output Devices
Allows the user to interact
Output devices deliver data
Monitor, printer, speaker
Some devices are input and output
Touch screens
2. Lecture 04: Roadmap
Output
Software brings the machine to Life
System Software
Application Software
Computer Data
Computer Users
The User’s Role
Userless Computers
1A-2
3. Essential Computer Hardware
Output
Text, Graphics, Audio, Video
Output Devices
Allows the user to interact
Output devices deliver data
Monitor, printer, speaker
Some devices are input and output
Touch screens
1B-3
5. Commonly Used Printers
Impact 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
4B-5
6. Commonly Used Printers
Dot matrix printers
Impact printer
Print entire line at a time
Used to print to multi-sheet pages
Print head strikes inked ribbon
9 to 24 pins. More pins high quality.
Speed measured in characters per
second(cps)
4B-6
8. Cont.
Line Printer
Entire line at one time
Speed measured by line per minute(lpm)
Some printers can print 3000lpm
Often connected to midrange mainframe
servers or network.
1B-8
9. Commonly Used Printers
Ink-jet printers
Non-impact printer
Inexpensive home printer
Black and white or Color output
Sprays ink onto paper
Speed measured in pages per minute
Quality expressed as dots per inch(resolution)
Use separate paper sheets placed in tray(ink
jet , photo, plain, glossy paper)
Catridge has holes to through ink.
4B-9
11. Commonly Used Printers
Laser printer
Non-impact printer
Produces high quality documents and high
speed printer.
Color or black and white
Print process
Laser beam draws text on special drum.
Toner sticks to text
Toner melted to page
Speed measured in pages per minute
Quality expressed as dots per inch
4B-11
14. High-Quality Printers
Special purpose printers
Used by a print shop
Output is professional grade
Prints to a variety of surfaces
4B-14
15. High-Quality Printers
Photo printers
Produces film or lab quality pictures
Prints very slow
Prints a variety of sizes(4*6, 3*5, letter legal
pages)
4B-15
16. Cont.
Thermal Printer
Pushing electrically heated pins against sensitive
paper.
Operation costs are low and images go fade over
time.
Two main types
Thermal Wax Printer
Dye Sublimation Printer
1B-16
17. High-Quality Printers
Thermal wax printers
Produces bold color output
Color generated by melting wax through heat
Operation costs are low
Output is slow
4B-17
18. High-Quality Printers
Dye sublimation printers
Produces realistic output
Digital photo printer
Use heat to transfer dye to special paper
Very high quality
Color is produced by evaporating ink
Operation costs are high
Output is very slow
4B-18
19. High-Quality Printers
Plotters
Large high quality blueprints,maps.
use row of charged wires to draw pattrens and
then fuse toner to pattren.
Operational costs are low
Output is very slow
4B-19
20. Cont.
Mobile Printers.
Label Printer:
Use thermal technology.
Use to generate bar codes.
Print adhesive type material to place on
envelopes, floppy disks, cds, dvds.
Postage Printer:
Type of label printer to print postage
stamps.
1B-20
21. Monitors
Most common output device
Connects to the video card
Categorized by color output
Monochrome
One color with black background
Grayscale
Varying degrees of gray
Color
Display 4 to 16 million colors
4A-21
22. Monitors
Cathode Ray Tube (CRT)
Most common type of monitor
Screen coated by phosphorus material(red
blue green)
Electrons fired from the back
Electrons excite phosphor to glow
Phosphor is arranged in dots called pixels
Dot mask ensures proper pixel is lit
Produces Electromagnetic Radiations(EMR)
risky for health.
23. Monitors
CRT color
Phosphor dots arranged in triads
Red, green, and blue dots
Three colors blend to make colors
Varying the intensity creates new colors
25. Monitors
Liquid Crystal Display (LCD)
Commonly found on laptops
Desktop versions exist
Solve the problems of CRT
Liquid cells sandwich between two sheets.
Fluorescent tube through lights on cells
Electric charges causes cells to twist.
Twisting allowed some light to pass and other
to block.
26. Monitors
Passive matrix LCD
Pixels arranged in a grid
Pixels are activated indirectly
Row and column are activated
Animation can be blurry
27. Monitors
Active matrix LCD
Each pixel is activated directly
Use separate transistors.
Pixels have 4 transistors
One each for red, green, blue
One for opaqueness
Transistors arranged in a thin film
Animation is crisp and clean
Also known as thin film transistor. Newer
version is LED
29. Monitors
Plasma monitor
Gas is excited to produce light
Voltage is applied to gas sandwich between
glass plates causes to produce ultraviolet UV
rays. UV brightens the pixels.
30. Monitors and Video Cards
Monitors impacts user effectiveness
Monitors should have
Crisp text
Clear graphics
Adjustable controls
Clear edges
31. Monitors and Video Cards
Size of monitor
Measured in inches
Measured diagonally
Actual size
Distance from corner to corner
Viewable size
Useable portion of the screen
32. Monitors and Video Cards
Resolution
Number of pixels on the screen
Higher number creates sharper images
Higher number creates smaller images
33. Monitors and Video Cards
Refresh rate
Number of time the screen is redrawn
Modern equipment sets this automatically
Improper settings can cause eyestrain
34. Monitors and Video Cards
Dot pitch
Distance between the same color dots
Ranges between .15 mm and .40 mm
Smaller creates a finer picture
Should be less than .22
35. Commonly Used Printers
MultiFunction peripherals
Scanner, copier, printer and fax
Popular in home offices
Prices are very reasonable
4B-35
36. Data Projectors
Replaced overhead and slide projectors
Project image onto wall or screen
Sometimes mounted on wall.
37. Data Projectors
Projectors
Two types
LCD projector
Connected to compuetr and use light source to show data.
Lower quality images
DLP Projectors
A series of mirrors control the display
May be used in a lighted room
Crisp clear bright colorful image.
38. Video Cards
Device between the CPU and monitor
Better cards result in better output
Removes burden of drawing from CPU
Have their own processor and RAM
Modern cards have up to 512 MB RAM
Capable of rendering 3D images
40. Sound Systems
Sound card
Device between the CPU and speakers
Converts digital sounds to analog
Can be connected to several devices
Modern cards support Dolby Surround Sound
41. Sound Systems
Headphones 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
42. Computer data
Fact with no meaning on its own
Stored using the binary number system
Data can be organized into files
1B-42
43. Computer users
Role depends on ability
Setup the system
Install software
Mange files
Maintain the system
“Userless” computers
Run with no user input
Automated systems
1B-43
Teaching tip
It is helpful to have examples of input and output devices in class. Stories of obscure input output devices are typically well received by the students.
Teaching Tip
Figure 4B.5 on page 163 provides an excellent rendering of how the print head works. Be sure to refer to the image as you teach.
Insider information
Nearly all of the electronics for the printer is kept in the ink cartridge. Thus, when the cartridge is replaced the printing components of the printer are replaced. Refilling cartridges is OK, but should not be reused more than 2-3 times.
Insider information
The laser printer works on a similar process to a photocopier. The first photocopier as we know it today was invented in Astoria NY in 1938 by Chester Carlson and Otto Kornei.
Teaching tip
Unless your students have spend a lot of time with HTML or graphics colors, they will have a hard time grasping how RGB values work. The best methods are to show them various colors and then let them experiment. The website www.lynda.com/hue.html provides decimal-value examples of RGB values. Once the students have seen different colors, open MS Paint and let the students develop their own colors. Challenge them to build pink, orange, brown and any of their favorite colors
Insider information
The limited viewing angle can be an advantage. For high security systems, low viewing angles stop casual glances at the screen.
Teaching tip
It is helpful to draw the relationship between viewable and actual size.
Insider information
Many CRT’s are capable of supporting several resolutions. LCD monitors in contrast often can only support one or two resolutions. The reason are the transistors on the LCD cannot move, while the electron gun on the CRT can simply aim for a smaller pixel.
If you are in a computer class, stop and have students adjust their resolution on the screen. The simplest method is to right click the desktop and select properties. Click the settings tab, and adjust the slider. As the students are experimenting, have a student answer why larger resolution numbers make smaller images. The answer is higher resolutions draw with smaller pixels.
Insider information
Whenever a TV camera films a computer monitor, the monitor seems to have a line moving up the screen. This is the monitor refreshing the pixels. The camera films faster than the eye can see, which is why the refresh is noticeable.
Insider information
A projector is rated in lumens. This is a measure of how bright the projector is. Higher lumens ratings result in a brighter projector. For a guide to lumens ratings, see http://www.projectorpeople.com/tutorials/lumen-guide.asp.
Insider information
The two leading video card families are ATI’s Radeon and NVIDIA’s GeForce line. Both offer exceptional graphics cards ranging from $50 to $600.
Insider Information
Sound Blaster is the primary manufacturer of sound cards. Exceptional models start at around $30.00.
Insider information
The PS2 game SOCOM II Navy Seals includes a USB headset to allow verbal communication with other team members.
Teaching tip
Chapter 5 in the text explores data processing in greater detail.
Figure 1B.5 shows data in binary format.
Teaching tip
Most computer problems are caused by user error. Given this fact, it is fun here to teach the student the acronym PEBKAC the Problem Exists Between Keyboard And Chair. A little humor can break up the lecture monotony.