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Output devices

  1. Output Devices
  2. The output unit is responsible for producing the output in user readable form. The function of an output device is to present processed data to the user. The computer sends output to the monitor if the user needs to see the output. The output is send to the printer whenever the output is needed in hard copy form. The sound output is produced with help of speaker. Graphic output is produced with the help of plotter. Output Devices
  4. MONITORS Monitor is the most common form of output from computer. It displays information in similar way to that shown on television screen. The picture on a monitor is made up of thousands of tiny colored dots. called Pixels.
  6. CATHODE RAY TUBE The CRT works in the same way as TV-it contains an electron gun at back of the glass tube. This fires electrons at groups of phosphor dots, which coat the inside of the screen. When the electron strike phosphor dots they glow to give color.
  8. LIQUID CRYSTAL DISPLAY TFT is the device within each pixel that sets the charge. And so sometimes they are called “Liquid Crystal Display” referring to the material they use. TFT is a variant of LCD technology. LCDs use much less power than a normal monitor.
  9. Plasma MONITOR
  10. Plasma MONITOR Plasma Monitors are flat panel display. The plasma technology utilizes small cells containing electrically charged ionized gases across the face of a plasma display, to collectively form a visual image.
  11. Touchscreen Monitor
  12. Touchscreen Monitor Touchscreen monitors are built by combining touch sensitive materials with a durable but sensitive outer material that protects the monitor from finger but still allows monitor to detect where a person is placing his fingers. This technology is used in Tablet PCs, checkout store terminals and smartphones.
  13. Organic light emitting display
  14. Organic light emitting display OLED is a light emitting display which has a film of organic compounds which emits light and responds to an electric current. This organic layer of semi-conductors is situated b/w 2 electrodes and atleast one of these electrodes is transparent. The organic molecules are electrically conductive as a result of delocalisation of pi electrons caused by conjugation over part or all the molecule. These materials have conductivity levels from insulators to conductors hence k/a semi-conductors.
  15. printers A most convenient and useful method by which computer can deliver information is my means of printed characters. Printers can be divided into two categories:  Impact Printers: There are mechanical contact between the print head and paper.  Non-Impact Printers: There is no mechanical contact between the print head and paper.
  16. Impact
  17. Line They print a line of text at a time, the full width of the page, rather than using a print head that moves back and forth. The speed of the line printer is measured by the number of line-per-minutes (lpm). Typical main-frame line printers (IBM) use a metal "band saw" character loop, and solenoids for each character position, typically 132 columns. The band spins at several RPS and as each letter aligns with the column it's intended to be, the solenoid, or hammer behind that column fires striking the letter through the ink ribbon, onto the paper.
  18. DrumIn a typical drum printer design, a fixed font character set is engraved onto the periphery of a number of print wheels, the number matching the number of columns (letters in a line) the printer could print. The wheels, joined to form a large drum (cylinder), spin at high speed and paper and an inked ribbon is stepped (moved) past the print position. As the desired character for each column passes the print position, a hammer strikes the paper from the rear and presses the paper against the ribbon and the drum, causing the desired character to be recorded on the continuous paper. Because the drum carrying the letterforms (characters) remains in constant motion, the strike-and-retreat action of the hammers had to be very fast. Typically, they were driven by voice coils mounted on the moving part of the hammer.
  19. Daisy WheelDaisy wheel printing is an impact printing technology invented in 1969 by David S. Lee at Diablo Data Systems. It uses interchangeable pre-formed type elements to generate high- quality output comparable to premium typewriters but two to three times faster. Daisy wheel printing was used in electronic typewriters, word processors and computers from 1972 The heart of the system is an interchangeable metal or plastic "daisy wheel" holding an entire character set as raised characters moulded on each "petal". Different typefaces and sizes can be used by replacing the daisy wheel. It is possible to use multiple fonts within a document: font changing is facilitated by printer device drivers which can position the carriage to the center of the platen and prompt the user to change the wheel before continuing printing.
  20. Dot-matrixA type of printer that produces characters and illustrations by striking pins against an ink ribbon to print closely spaced dots in the appropriate shape. Dot-matrix printers are relatively expensive and do not produce high-quality output. However, they can print to multi-page forms (that is, carbon copies), something laser and ink-jet printers cannot do.  · speed: Given in character per second (cps),the speed can vary from about 50 to over 500 cps. Most dot-matrix printers offer different speeds depending on the quality of print desired.  · print quality: Determined by the number of pins (the mechanisms that print the dots), it can vary from 9 to 24. The best dot-matrix printers (24 pins) can produce near letter-quality type, although you can still see a difference if you look closely.
  21. Non- Impact
  22. Electromagnetic A magnetic of what is to be printed can be written on a drum surface. Then this surface is passed through magnetic powder which adheres to charge areas. The powder is passed onto paper. Speeds of upto 250 characters per second are obtained in such system.
  23. Thermal Thermal printer is a printer that uses to transfer an impression onto paper. It is a high quality printer invented by “JACK KIBLY”. And it is usually faster than impact dot matrix printers. They are also smaller, lighter and consume less power, making them ideal for portable.  There are two types of thermal printers:  Direct thermal  Thermal wax transfer
  24. electrostatic Electrostatic printing is a printing technique done without any plate, ink or type form. The paper is coated with a thin layer of zinc oxide, making it an insulator in the dark and simultaneously a conductor of electricity when exposed to light. These machines are used for printing of geographic maps. With the advancement in technology and higher speed, the machines are also being used to print small books. Electrostatic printers are used for short run printing as they are faster and also do not cost much.
  25. inkjet Some printers direct a high- velocity stream of ink towards paper. This stream is deflected, generally by passing through an electrostatic field such as that used to deflect beams in oscilloscopes. In some ink stream is broken into droplets by an ultrasonic transducer.
  26. laser Laser printing is an electrostatic digital printing process. It very rapidly produces high- quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back & forth over an electron-charged, cylindrical drum, to define a differentially- charged image. The drum then selectively collects electrically-charged, powdered ink (i.e., toner), and transfers the image to the loaded paper, which is then heated in order to permanently fuse the text/imagery. As with digital photocopiers and multifunction/all-in- one inkjet printers, laser printers employ a xerographic printing process; but, laser printing differs from analog photocopiers in that the image is produced by the direct scanning of the medium across the printer's photoreceptor. This enables laser printing to copy images more quickly than most photocopiers.
  27. Multifunction An MFP multifunctional is an office machine which incorporates the functionality of multiple devices in one, in addition to printing, can scan, copy and, in many cases, send and receive faxes. Some newer all-in-one printers can connect directly to the web, so they can print web pages, emailed documents or documents stored in the cloud without being hooked up to a computer. Almost all printer manufacturers offer multifunction printers. They are designed for home, small business, enterprise and commercial use. Naturally, the cost, usability, robustness, throughput, output quality, etc. all vary with the various use cases.[citation needed] In the commercial/enterprise area, most MFP have used laser-printer technology, while the personal, SOHO environments, utilize inkjet methods.
  28. Speaker
  29. Computer speakers, or multimedia speakers, are speakers external to a computer, that disable the lower fidelity built-in speaker. They often have a low-power internal amplifier. The standard audio connection is a 3.5 mm (approximately 1/8 inch) stereo phone connector often color-coded lime green (following the PC 99 standard) for computer sound cards. A few use aRCA connector for input. There are also USB speakers which are powered from the 5 volts at 500 milliamps provided by the USB port, allowing about 2.5 watts of output power. Computer speakers were introduced by Altec Lansing in 1990. Speaker
  30. plotter
  31. plotterThe plotter is a computer printer for printing vector graphics. In the past, plotters were used in applications such as computer-aided design, though they have generally been replaced with wide- format conventional printers. A plotter gives a hard copy of the output. It draws pictures on paper using a pen. Plotters are used to print designs of ships and machines, plans for buildings and so on.
  32. 3d printer
  33. 3d printerThe process of 3D printing, which is what created this likeness of the Star Wars character Yoda, has gained in popularity in recent years. There are several types of 3D printers, but all involve the same basic approach for “printing” an object: transferring a substance in multiple layers onto a building surface, beginning with the bottom layer. A Dutch architect recently announced plans to construct a house using 3D printing, a technology that has been around for decades but has only entered the public consciousness in the last few years.
  34. A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen. Projector