Output Devices -Types of Output Devices

Types of Output Devices

1. Monitor

2. Sound System
3. PC Projector (Data Show)
4. Printer

Monitor

 It is the most common output device.

 Shape of monitor is just like a T.V set.
 Function of monitor is to display output on its screen.
 Any picture is made up of small dots called Pixels.
 Two technologies used in monitor are Cathode Ray Tube (CRT)
Liquid Crystal Display (LCD) or Flat Screens

CRT Monitor

 Most computer monitors are based on CRT.

 Relatively low in cost.
 Uses a large vacuum tube, called CRT (cathode ray tube).
 There are three electron guns one for each color that are RED, GREEN and BLUE (RGB).
 A beam of electrons emitted by electron gun makes an image on screen.
 Monitor’s screen coated with phosphors chemical that glow when they are struck by the electron beam.
 Phosphors dots known as Pixels.

LCD (Liquid Crystal Display)

 Also called Flat Screen monitors.
 Liquid crystal displays (LCD) are flat screen.

 Better picture quality than CRT monitor.

 Flat screen monitors having no electron gun.
 Image will made up with the help of liquid.
 This technology is very expensive.

Comparing Monitor

Size

14-inch, 15-inch, 17-inch, etc
Refresh Rate

Number of times the electron gun scan every pixel is called Refresh Rate. Measured in cycles per seconds (cps)

Resolution

640(H) X 480(V), 600 X 800, 1024 X 768, 1152 X 864, 1280 X 1024

Dot pitch
Distance between phosphor dots is known Dot pitch.

PC Projector

 Projects a video output onto an external surface.

 Typically weight less than 10 pounds.
 Can display 16 millions colors.
 Support up to 1024 X 768 resolution.
 Used to display still images, animated pictures or full video

Sound System

 Speakers (common Output device)

 Sound is defined as air pressure.
 Magnet produces the air pressure.
 Sound card translate digital sound into electric current that is sent to the speakers.

Printers

 Printers are used to produce hard copy of output.

 Printers can print text and graphics.
 Printers are available in both color and black & white.
 The port of printer is called LPT1.
 Main difference in printers depends on Quality of output
Ability to print graphics Printing speed

 Printer are classified into two groups

1. Impact Printer

2. Non-Impact Printer

Impact Printer

 Prints the paper with the strikes of hammer, Pins or a ribbon

 Works like the typewriter
 Example are:
o Dot Matrix Printer, Electric Typewriter, Line Printer, Band Printer

Dot Matrix Printer

 Print one character at a time.

 Typical matrix is 5×7 (5 wide, 7 high)
 Uses color or black magnetic ribbon to print data.
 Can print 200 to more than 1000 character/minute
 Less expensive
 Can also print charts, pictures, or different symbols

Non-Impact Printer

 Uses laser or inkjet technology.

 High in speed
 Best in quality
 High in cost
 Example are:
o Laser Printer o inkjet Printer

Inkjet Printer

 Is a non-impact printer

 It creates output on paper by a spray of ink
 Electric field control the spraying jet
 Produce one character at a time
 Quality is higher than dot matrix
 Can print 1 page to 8 pages per minute
 Color inkjet printers are also available

Laser Printer

 Is a non-impact printer, also called page printer

 LASER stands for Light Amplification by Stimulated Emission of Radiation

 Can print one page at a time
 Buffer holds the data and print
 Can print 5 to 300 pages per minute
 Very high in cost or quality