Input and output devices

Input and output devices

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  INPUT DEVICES Input devicesare the devices which take in data. The Input devices can be classified into 7 groups, they are:-  Touch Screens  Magnetic Stripe Readers  Barcode Scanners  OMR Devices  OCR Devices  MICR Devices
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  TOUCH SCREENS  Selectionis done without need of pointing device(simply touching the icon /button)  Used at petrol stations, ATMs, point of sales terminals, airports, interactive boards, PDAs.  Advantages- Faster entry of data, tamper proof.  Disadvantages- Limited options, frequent uses can lead to health problems and issues
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  SOME TOUCH SCREENDEVICES
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  MAGNETIC STRIPE READERS Used at the back of all the credit cards  Security cards for the entry to the building  Advantage: Fast input, error free
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  SMART CARD READERS Contains chip to store data  Data update is possible  Used in identity cards  Advantages: Reduces cash transaction  Disadvantage: If the card gets lost then it may lead to identity theft
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  BARCODE READERS  Usedto read information in bar-coded format  Used in supermarkets, library, etc  Advantage: Faster data entry  Disadvantage: Expensive system to the administrator
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  OMR DEVICES  OMR(OpticalMark Recognition)  Used to read marks written by pen/pencils such as questionnaires, multiple choice examinations, forms, etc  Advantage: Fast input, accurate  Disadvantage: Forms need to be designed very carefully, time consuming as need to be checked manually.
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  OCR DEVICES  OCR(OpticalCharacter Recognition)  Basically a software that converts scanned text into computer readable format.  Used in processing of passports and identity cards  Advantage: Faster data entry, less errors  Disadvantage: Not accurate in reading.
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  MICR DEVICES  MICR(MagneticInk Character Recognition)  Reads characters printed in special ink(iron particles)  Used to process cheque in banking operation  Advantage: Secure as printed characters which can’t be altered, less errors, data can be read if overwritten  Disadvantage: Only certain character can read expensive
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  OUTPUT DEVICES  Monitors:CRT, TFT, LCD, LED  Printers: Inkjet, Laser, Dot-Matrix Printers  Plotters  Multimedia projectors
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  CRT(CATHODE RAY TUBE)MONITOR Less expensive, used with light pens, uses electron gun-phosphor screen  Advantages: Produces good quality images, angle of viewing is better, supports light pen  Disadvantages: Very heavy, consume more power, runs very hot, flickering can lead to headache
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  TFT(THIN FILM TRANSISTORS) Tiny pixels made up of transistors controlled by microprocessor, each pixel has three transistors.  Advantages: Lightweight, less glare than CRT, less radiation, consumes less power, do not generate heat compared to CRT.  Disadvantage: Angle of viewing, expensive, not suitable for using light pen
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  LASER PRINTER  Usedin offices for high quality output. They are faster  Advantage: Fast for high volumes, high quality  Disadvantage: Expensive, particular type of paper size and sheets can be used, health hazards, heavy
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  INK JET PRINTERS Used for cost effective good quality output at home, offices, etc.  Advantages: Less expensive, portable, light weight  Disadvantage: Slow as little buffer capacity, ink can smudge , ink cartridges run out very quickly
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  DOT- MATRIX PRINTERS Type of impact printer, used for low-quality output in banks, post offices, railway tickets.  Advantage: Less expensive, carbon copies can be produced, use of continuous stationary.  Disadvantage: Noisy, slow, not good for images
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  3-D PRINTERS  Usedto produce 3-D models (prototypes) using modified inkjet technology(Tomography). Thin layers of fine powder(plaster, resin and starch) is used to make 3D models  Advantage: Money saving, gives better idea of end product, powder can be produced/re-used.  Disadvantage: Expensive, slow, requires finishing touch on the end products.
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  PLOTTER  Used formaking large drawings and images(blue prints of building, factories, etc)  Advantages: High quality images, huge products  Disadvantage: Slow, expensive
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  MULTIMEDIA PROJECTORS  Itmagnifies and project the signals onto a big screen received by TV,DVD  They are used for training advertising presentations when large number of audience is present. Home cinema systems  Advantages: Useful for much larger number of audience, number of need several computers to use for one.  Disadvantage: Fuzzy, blurred images, expensive, setting up a projector is difficult