Input And Output Devices Of A Computer Essay

The c all(prenominal) input and payoff be employd both asverbs to report the process of immortalizeing / periling the data. nouns referring to the data itself entered into /displayed by the information processing system.Input DevicesInput devices atomic number 18 necessary to convert information or data in to a form which hind end be understood by the computer. A bang-up input device should provide timely, dead-on(prenominal) and designful data to the briny memory of the computer for processing.KeyboardKeyboard is the standard input device attached to all computers. The layout of a keyboard is just the like the traditional facewriter of the type QWERTY. It everyplacely contains approximately extra command keys and function keys. It contains a total of 101 to 104 keys.You gain to press correct combination of keys to input data. The computer bed neck the electrical signals corresponding to the correct key combination and processing is do accordingly. The computer k eyboard is utilize to enter school text information into the computer. The keyboard digest also be accustom to type commands directing the computer to perform reliable actions. Commands argon typically chosen from an on- block out menu using a crawl, simply in that location be often keyboard shortcuts for giving these same commands. keyboards usually reach a numeric key plod, a bank of editing keys, and a language of function keys along the top. Laptop computers dont have manner for large keyboards.they intromit a fn key so that other keys croup perform double duty. just about keyboards attach to the PC via a PS/2 connector or USB port.Pointing DevicesThe graphical giver interfaces (GUIs) in use today requires some kind of device for positioning the on-screen cursor. Typical pointing devices argonmouse,trackball,touch pad,trackpoint, prowess tablet, marijuana cig bette,touch screen.Pointing devices atomic number 18 connected to a PC via a serial ports (old), PS/2 mo use port (newer), or USB port (newest).MouseA mouse is an input device that is use on personal computer. It ruffles on a itty-bitty ball and has ii or three b atomic number 18lytons on the top. When rolled crossways a planar surface the screen censors the mouse moves in the direction of mouse movement. In older mice, a ball in the bottom of the mouse rolls on the surface as it moves. internal rollers sense the ball movement and expect the information to the computer via the cord of the mouse. The newer optical mouse uses a easygoing up and a splendid optical sensor to detect the motion of the mouse by tracking a flyspeck send off of the desk surface. Optical mice parry the problem of dirty mouse ball, which causes regular mice to roll unsmooth. A cordless or wireless mouse communicates with the computer via radio waves. such mice enquire internal batteries.A mouse also includes wizard or much exactlytons (and possibly a scroll wheel) to allow users to interact with the GUI. The traditional PC mouse has two buttons, while the traditional Macintosh mouse has one button. On either type of computer you can also use mice with three or more buttons and a slender scroll wheel. jibe padMost laptop computer computers have a touch pad pointing device.  Moving the on-screen cursor is done by sliding a thumb along the surface of the touch pad. The buttons are located below the pad, but intimately touch pads allow you to perform mouse clicks by tapping on the pad itself. Touch pads have the advantage over mice that they take up much less room to use. They have the advantage over trackballs that there are no moving parts to get dirty and sequel in jumpy cursor control.TrackpointSome sub-notebook computers, which lack room for horizontal a touch pad, incorporate a trackpoint. a small preventative projection embedded between the keys of the keyboard. The trackpoint acts like a little joystick that can be employ to control the position of the on-s creen cursor.TrackballTrackball is sort of like an upside-down mouse, with the ball located on top. A is fingers is used to roll the trackball, and internal rollers sense the motion which is circulari fastened to the computer. Trackballs have the advantage over mice in that the body of the trackball remains stationary on a desk, so much room is not admited to use the trackball. Early laptop computers often used trackballs.Touch screenSome computers, especially small hand-held PDAs, have touch sensitive display screens. The user can make choices and press button exposures on the screen. Stylus is often used, which you tolerate like a pen, to write on the surface of a small touch screen.Graphics tabletA graphics tablet consists of an electronic writing area and a special pen that works with it. A graphics tablet allows artists to create graphical images with motions and actions similar to using more traditional drawing tools.JoysticksJoysticks and other game controllers can al so be connected to a computer as pointing devices. They are generally used for playing games, and not for imperative the on-screen cursor in productivity software program.ScannersA scanner is a device that images a imprinted page or graphics by digitizing it, producing an image made of tiny pixels of different brightness and emblazon values which are represented numerically and sent to the computer. Scanners scan graphics and pages of text which are consequently run through OCR (Optical section Recognition) software that identifies the individual letter shapes and creates a text file of the pages contents. The common optical scanner devices areMagnetic sign Character Recognition (MICR),Optical Mark ref (OMR) ,Optical Character Reader (OCR).Magnetic Ink Character Recognition (MICR)This is widely used by banks to process large volumes of cheques and drafts. Cheques are put inside the MICR, as they enter the reading unit, the cheques pass through the magnetic field which causes the read detail to recognize the character of the cheques.Optical Mark Reader (OMR)This technique is used when students have appeared in objective type tests and they had to mark their answer by darkening a square or circular space by pencil. These answer sheets are directly fed to a computer for marker where OMR is used.Optical Character Recognition (OCR)This technique unites the direct reading of each printed character. Suppose you have a set of hand written characters on a piece of piece. You put it inside the scanner of the computer. This pattern is compared with a site of patterns stored inside the computer. Whichever pattern is matched is called a character read. Patterns that cannot be identify are rejected.MicrophoneA microphone is attached to a computer to record lumbering.The kick the bucket is digitized and stored in the computer to later processing and playback. midi DevicesMIDI (Musical Instrument Digital Interface) is a system designed to transmit informatio n between electronic musical theater instruments. A MIDI musical keyboard can be attached to a computer and allow a performer to play music that is captured by the computer system as a sequence of notes with the associated timing.Output DevicesVisual Display Unit (VDU)The most popular output device is the VDU.The VDU is also called monitor.Monitor is used to display the input data and to receive messages from the computer. It has its own box which is separate from the main computer system and is connected to the computer by a cable. In some systems it is compact with the system unit.It can be colourise or monochrome.cathode-ray tube MonitorTraditional output device of a personal computer has been the CRT (Cathode Ray Tube) monitor. It contains a large cathode pecker tube that uses an electron beam of varying strength to paint a picture onto the vividness phosphorescent dots on the inside of the screen. CRT monitors are heavy and use more electrical power than prostrate embelli sh displays. CRT are preferred by some graphic artists for their accurate color rendition, and preferred by some gamers for faster response to quickly changing graphics. Monitor screen size is measured diagonally across the screen, in inches. Not all of the screen area may be usable for image display, so the viewable area is also specified.The dissolvent of the monitor is the maximum number of pixels it can display horizontally and vertically (such as 800 x 600, or 1024 x 768, or 1600 x 1200). Most monitors can display several resolutions below its maximum setting. Pixels (Picture Elements) are the small dots that make the image displayed on the screen. The spacing of the screens tiny phosphor dots is called the dot pitch (dp), typically .28 or .26 (measured in millimeters). A screen with a smaller dot pitch bewilders sharper images.Computer must produce a icon signal that a monitor can display. This may be handled by circuitry on the motherboard, but is usually handled by a vi deo card in one of the computers expansion slots often the slot is a special one employ to video use, such as an AGP slot (Accelerated Graphics Port). Video separate are also called video display adapters, and graphics cards. Many video cards contain separate processors and dedicated video memory for generating labyrinthian graphics quickly without burdening the CPU. directly Panel MonitorA flavorless venire display usually uses an liquid crystal display (Liquid Crystal Display) screen to display output from the computer. The LCD consists of several thin layers that polarize the light exceedingly through them. The polarization of one layer, containing long thin molecules called liquid crystals, can be controlled electronically at each pixel, blocking varying amounts of the light to make a pixel lighter or darker. Other types of flat panel technology exist (such as plasma displays) but LCDs are most comm unaccompanied used in computers, especially laptops. Older LCDs had lessen response times and low contrast, but active matrix LCD screens have a transparent thin film transistor (TFT) controlling each pixel, so response, contrast, and viewing angle are much improved. Flat panel displays are much lighter and less bulky than CRT monitors. They consume much less power.They are more expensive than CRTs, but the price gap is narrowing. The display size of a flat panel is expressed in inches, and the resolution is the number of pixels horizontally and vertically on the display.TerminalsTerminal is a very popular interactive output unit.It is dissever into two types gruelling reduplicate margeinals.soft copy terminals.A hard copy terminal provides a printout on paper.A soft copy terminals provides visual copy on monitor.PrinterPrinter is an important output device used to get a printed copy of the processed text or result on paper. There are different types of printers that are designed for different types of applications Depending on their speed and ap proach of printing. printers are sort asimpact.non-impact printers.Impact printersImpact printers use the familiar typewriter approach of lb a typeface against the paper and inked ribbon. Dot-matrix printers are of this type.  Dot matrix printers use small electromagnetically activated pins in the print head, and an inked ribbon, to produce images by impact. These printers are slow and noisy, and are not commonly used for personal computers anymore they can print multi-layer forms, which neither ink jet nor optical maser printers can.Non-impact printersNon-impact printers use electro-static chemicals and ink-jet technologies. Laser printers and Ink-jet printers are of this type.This type of printers can produce color printing and elaborate graphics.Ink Jet PrinterFor hardcopy output, you need some kind of printer attached to the computer. The most common type of printer for home systems is the color ink jet printer. These printers form the image on the page by spraying tiny droplets of ink from the print head. The printer needs several colors of ink (cyan, yellow, magenta, and cruddy) to make color images. Some photo- character ink jet printers have more colors of ink. Ink jet printers are inexpensive, but the cost of consumables (ink cartridges and special paper) makes them costly to melt in the long run for many purposes.Laser PrinterA laser printer produces good quality images by the same technology that photocopiers use. A drum coated with photosensitive material is charged, and then an image is written onto it by a laser (or LEDs) which makes those areas lose the charge. The drum then rolls through toner (tiny plastic particles of pigment) that is attracted to the charged areas of the drum. The toner is then deposited onto the paper, and then fused into the paper with heat.Most laser printers are monochrome, but more expensive laser printers with multiple color toner cartridges can produce color output. Laser printers are faster than ink jet pri nters.Their speed is rated in pages per minute (ppm).They are more expensive than ink jets, but they are cheaper to run in the long term if you just need good quality black & white pages.Other PrintersMulti-function printers are available that not only operate as a computer printer, but also include the hardware needed to be a scanner, photocopier, and FAX machine as well.Sound OutputComputers also produce sound output, ranging from simple beeps vigilance the user, to impressive game sound effects, to concert quality music. The circuitry to produce sound may be included on the motherboard, but high quality audio output from a PC usually requires a sound card in one of the expansion slots, connected to a set of good quality external speakers or headphones. Multimedia is a term describing computer output that includes sound, text, graphics, movies, and animation. A sound card is an example of a multimedia output device .