Output Hardware

                       Output Device 

The derivation of the final result as meaningful information for the user after processing is called output. It can appear in a variety of forms such as text, graphics, audio and videos. There are two types of output devices. They are

• Soft copy output


• Hard copy output

                   Computer Monitor

Computer monitor is the most popular output devices used today for processing soft-copy output. It displays a wide variety of information, including text, images, icons, video and animations. The basic types of monitors used today are :

• 
  LCD ( Liquid Crystal Display ) : A  flat-panel monitor that uses special kind of liquid crystal to display the character and graphics are called LCD monitor. They are portable in size but expensive than CRT monitor. They provide a wide viewing angle and come in sizes typically ranging from 17-inches to 60-inches. 


• 
  CRT Monitor :  Common monitor that uses a large vacuum tube called Cathode Ray Tube. It looks like a common TV screen. It is old type of monitor.         


• 
  OLED (Organic Light Emitting Display) computer monitors :  OLED computer monitors are the much thinner and LCD or Plasma screens. OLED monitors can also be placed on transparent surfaces, such as glass, allowing the user to see through them when not active.                                                                                          

                                     Printer 

A printer is an output device that produces text and graphics on a physical medium such as paper. Printer information is called hard copy because the information exists physically and is permanent form of output. Computer printer are commonly divided into two general classes according to the way they  produce images on paper. They are :

• 
  Impact Printer :   Impact printer is a printer that prints the character like typewriters which characters are printed by physical striking over an inked ribbon. It is slow and poor quality printer. It is noisy printer but it is a cheaper for operation.


• 
  Non-impact Printer : Non-impact printer is a printer that prints the character using heat, light and ink spray technique. It is quite printer. It is faster than Impact printer. Its quality is good but it is expensive than impact printer. 

                Some Popular Printers 

Ink-jet printer : 

Ink-jet printer is a high quality non-impact printer that forms characters by spraying small drops of ink onto the paper. They are most popular printers for home use. Currently, most inkjet printers use either thermal inkjet. Inkjets are usually inexpensive, quite in operation and produce high-quality output.

* The thermal inkjet principle was discovered by Canon engineer Ichiro Endo in August 1957.

Laser Printer :

Lase printers are high-speed, high-quality printers that use laser beam to form images on paper using toner ink as a medium. Unlike inkjet printers, laser printer use toner (Black or color powder) instead of liquid inks.  Laser printers are very expensive but they produce high-quality output. It takes warm up time to print. A laser printer consists of these three major components : drum cartridge, rotating mirror, toner cartridge and roller.

Dot Matrix printer :

Dot matrix printer is an impact printer that uses a movable print head consisting of pins. It produces text and graphics, when tiny wire pins on the print head strike the ink ribbon. The speed of dot matrix printer is measured in characters per second (cps). Dot matrix printers are inexpensive and relatively fast, but they do not produce high-quality output. It is noisy in sound and its has low printing speed.

Plotter :

Plotter is a printer that interprets commands from a computer to make line drawings on paper with one or more automated pens. It has high quality drawing and graphics. There are two types of plotters : Drum plotters, and Flat bed plotters.

Modem :

The full form of Modem is Modulator Demodulator. It is an input as well as output device. It converts analog signals i.e. signals from wave and the cable to digital signal i.e. signal used by the computer to process the data and vice-versa.