4-Input and Output Devices
CRT Monitor
(Cathode ray tube) generally the cheapest form of monitor. They are also the oldest and are extremely chunky. Output device
MICR
(Magnetic ink character recognition) It helps the reader to 'see' the shapes of the characters clearly.The characters can be read by humans as well as the programme. The numbers on the bottom of a cheque are printed using magnetic ink so that they can be read by a special reader even if they have been written over
OCR
(Optical Character Recognition) If a scanned image contains text, you can use software to turn it into text that can be used by a word processor. OCR is helpful for Blind people or for passports scanned!
OMR
(Optical Mark Reader) A scanner can also be used to scan sheet of paper looking for marks on the paper, such as multiple choice.
TFT Monitor
(Thin Film Transistor) These screens have a similar size display area, but the they are far thinner and lighter than the CRT monitor. (Output device)
Bar code reader
A bar code reader is a set of short parallel lines in contrasting colours, often black and white. Bar codes are read by devices that shine a laser at them and then read the reflection to tell how the thick lines are.
Multimedia Projector
Are devices that can project an image from a computer onto as large a surface as is necessary.
Qwerty Keyboards
Gets its name from the arrangement of letter on the top line of keys.
Flatbed plotter
Have the pen lying flat under the pen,
Plotters
They are line-drawing devices.
Inkjet printers
They work by squirting ink at the page out of different nozzles for different coloured ink.
Dot matrix printers
Use a set of pins to press an inked ribbon against paper.
Laser Printer
Work by using a laser to draw the required output onto a drum.
An optical mark reader is used for reading and inputting pencil marks on a form such as a school register or examination answers; any application involving input of a choice of options
optical mark reader
Concept keyboards
unlike qwerty keyboards, allow the user to decide what each keys should stand for and they can be changed when necessary
What are the types of pointing devices?
A mouse,Touchpad,Trackerballs,Joysticks
Control Application
Sensors and control devices together with the controlling computer make up a control application
Direct Input Systems
Some devices, such as optical mark readers, enable dat to be entered directly, without human intervention. These direct input or direct data entry methods are used when large amounts of similar data need to be entered.
Actuator
The device that turns the computer signal into movement is called actuator.
Manual Input Devices
The devices that are used by people to enter data themselves. Keyboards, pointing devices, cameras, scanners and microphones.
Drum plotter
The paper lies on a drum that spins to drive the paper under the pen while the pen itself moves across the drum.
Graphics tablet
is a very large touchpad. It senses the movement of an object moving over its surface and sends this information to the computer
A trackerball is a pointing device used by people with limited motor skills such as young children or those with disabilities.
trackerball