input and output devices
DESCRIPTION
for 6th graders and aboveTRANSCRIPT
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INPUT DEVICES
Input devices are 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
TOUCH SCREENS
Selection is 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
SOME TOUCH SCREEN DEVICES
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
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
BARCODE READERS
Used to read information in bar-coded format
Used in supermarkets, library, etc
Advantage: Faster data entry
Disadvantage: Expensive system to the administrator
OMR DEVICES
OMR(Optical Mark 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.
OCR DEVICES
OCR(Optical Character 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.
MICR DEVICES
MICR(Magnetic Ink 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
OUTPUT DEVICES
Monitors: CRT, TFT, LCD, LED
Printers: Inkjet, Laser, Dot-Matrix Printers
Plotters
Multimedia projectors
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
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
LASER PRINTER
Used in 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
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
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
3-D PRINTERS
Used to 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.
PLOTTER
Used for making large drawings and images(blue prints of building, factories, etc)
Advantages: High quality images, huge products
Disadvantage: Slow, expensive
MULTIMEDIA PROJECTORS
It magnifies 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