1. Output Devices

2. Output Processed input data into a useful form is called output
Computer generates several types of output depending upon the hardware and software used and requirements of the user
View output on the screen
Print it on printer
Hear it through speakers or headsets

3. Classification of Output
Softcopy Output
Hardcopy Output
Sound Output

4. Output devices Hardware component used to get output from the computer
Number of output devices are available
Most commonly used output devices include:
Monitor
Printer
Speaker
Head set
Fax Machine

5. Monitor Most popular and commonly used output device
Consists of screen and an electronic component that produce the output on the screen for a temporary period
Output received on the screen is called soft copy
Display texts, graphics and video information
Categories of Monitor:
Monochrome Monitors
Grayscale Monitors
Color Monitors

6. Types of Monitor
CRT Monitors
Flat-Panel Monitors

7. CRT Monitors Similar to standard television
Contains a Cathode Ray Tube which is a large scaled glass tube
Contains electronic gun

8. CRT Monitors

9. CRT Monitor

10. CRT Monitor Size
Measured diagonally, in inches across the front of the screen
Available in various sizes i.e. 15,17,19, 21 and 22 inches

11. Measuring Quality of CRT Monitor
Resolution
Dot Pitch
Refresh Rate

12. Video Card
Many CRT monitors use an analog signal to create an image on the screen
Video card is installed on the motherboard
Converts the digital output from the computer into analog video signal

13. Video Standards Standard Resolution Maximum Color
Monochrome Display Adapter (MDA)
720 X 350 1
Video Graphic Array (VGA)
640 X 480 16
Extended Graphics Array (XGA)
1024 X 768
256
Supper Video Graphics Array (SVGA)
800 X 600
1280 X 1024
1600 X 1200
16.7 million
Beyond SVGA
1920 X 1440
2048 X 1436

14. Flat Panel Monitor Also called LCD Monitor
Uses a Liquid Crystal Display to produce output on screen
Has fluorescent tube that emit light waves towards the liquid crystal cells
Takes less desk space
Consumes less power

15. Flat Panel Monitor

16. Flat Panel Monitor

17. Categories of LCD
Active Matrix LCD
Passive Matrix LCD

18. Touch Screen Monitors
Special monitors through which input data is directly entered by touching the screen with user fingertip
Use sensors in the computer screens to detect the touch of a finger
Example: ATM

19. Printers
Most commonly used output device used to get prints of documents on the paper
Output printed on the paper is called hardcopy
Printer is connected to a parallel port or a USB port of the system unit by a cable
Classification of printer based on printing mechanism:
Impact Printer
Non Impact Printer

20. Impact Printers
Print character and graphics on the paper with the strikes of hammer on a ribbon
Example: typewriter
Each hammer is embossed with the shape of alphanumeric character
Shape is printed on the paper through inked ribbon
Most commonly used printer is dot matrix printer

21. Non Impact Printers
Produce the output on the paper without striking the paper
Use electrostatic, chemicals, inkjet and thermal technologies for printing
Main features:
Faster than Impact
Print high quality output
Produce no noise during printing
Examples: Laser Printer, Inkjet Printer

22. Dot Matrix Printer Impact character printer
Print one character at a time
Prints output on the paper by using the mechanism called print head
Contains matrix of tiny pins arranged in row and columns
Can use tractor feed paper
Print head contain 9 to 24 pins
Speed is measured by the number of characters per second

23. Dot Matrix Printer

24. Inkjet Printer Non Impact character printer
Prints one character at a time
Has fine spray nozzle that creates the image of character or graphics on the paper by spraying tiny or small drops of ink onto the paper
Speed is measured in terms of number of pages per minute it can print

25. Inkjet Printer

26. Laser Printer Fastest and high quality non impact printer
More expensive
Work like photocopier
Creates image on the paper using a laser beam and powdered ink, called toner

27. Laser Printer

28. Plotters
Special output devices used to produce hard copies of graphs and design on the paper
Typically used to print large format graphs or maps such as construction maps or engineering drawings
Two Types:
Drum Plotters
Flatbed Plotters

29. Drum Plotters Also known as roller plotter
Consists of drum or roller on which a paper is placed
Drum rotates back and forth to produce the graph on the paper
Also consists of mechanical device known as robotic drawing arm that holds a set of colored ink pens or pencils

30. Flatbed Plotters Also known as Table Plotter
Plots on paper that is spread and fixed over rectangular flatbed table
Uses two robotics drawing arms

31. Flatbed Plotters Also known as Table Plotter
Plots on paper that is spread and fixed over rectangular flatbed table
Uses two robotics drawing arms

32. Flatbed Plotters

33. Other Output Devices Data Projectors Speakers
Computer Output Microfilm and Microfiche

34. References
Introduction to Information Technology by Riaz Shahid, CM Aslam and Safia Iftikhar
The Concepts of Information Technology by Imran Saeed, Ahsan Raza, Tariq Mehmood and Zafar Hussain