input and output devices

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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