1.1.3 input and output Flashcards
input/output devices and how they can be applied to the solution of different problems
what is an input device?
a peripheral used to provide data and control signals to a computer system
what is a barcode?
a means of representing data in a machine-readable form
what are check digits used for?
validation
what are check digits?
an extra digit or character added to the end of long code
how are check digits used?
applying an algorithm to the other digits, the long code is entered, the check digit is calculated and compared to the check digit at the end of the code
what are the advantages of barcode readers?
theyre common - reliable and well understood
what are qr codes used for?
providing a link to a particular page or website etc
what are the advantages of qr over barcode?
higher storage capacity
how are qr codes read?
codes are captured and read by taking an image with a dedicated scanner or a mobile device
what are rfid used for?
allows data to be transmitted wirelessly over radio waves
what are the two parts of a rfid system?
a tag and a reader
where are rfids used
id cards, library cards, transport systems, track animals (identification)
how do passive devices work?
no power supply, device is powered by radio energy transmitted by the reader - energy from the transmitter activates the chop
what is the range of passive devices?
up to 1 metre
how do active systems work?
small battery within the tag - will transmit its identifier at regular intervals
what is the range of active systems?
up to 200 meters
what are examples of manual input systems?
keyboard, mouse
what are examples of automated input systems?
sensor
what is an output device?
peripherals that reproduce or display data and information from a computer system
what are the 4 types of printer?
inkjet printer, laser printer, plotter, 3D printer
what type of ink and paper is used with an inkjet printer?
liquid ink - black/white or colour
high end can handle specialist paper at very high resolutions
what printer is the most suitable for printing photographs?
inkjet printer - produces rich colours
what are inkjet printers used for?
photographers and at home - low upfront cost
what is a disadvantage of inkjet printers?
the cost of ink is high
where are laser printers used?
the workplace
what are the advantages of laser printers over inkjet?
faster - one whole page at a time, high spec - capable of producing hundreds of pages per minute
what do laser printers use to print?
a powdered ink called toner
what type of image can a laser printer print?
very good for text, but not good for photos - difficult for deep rich colours
how does a plotter work?
uses one or more pens to draw an image - pens are lifted or applied to the paper as required
what are the advantages of plotters?
produces very precise drawings, can handle very wide paper, allows repeated layers to be printed
where are plotters used?
engineering and architectural practices
what do 3D printers use and how do they work?
filament - usually in the form of plastic-based resin which is heated and printed layer by layer to form a solid object
what are the two types of display screens?
lcd screens and led displays
what are the advantages of liquid crystal display?
low cost, most common display
where are lcd used?
standard desktop and laptop computers
what are the advantages of light emitting diode displays?
uses less power than lcd, so led are cheaper and more environmental friendly
what are oled screens?
organic light emitting diode - a varient on led displays
what are the advantages of oled over led?
lighter and more flexible
where would oled be used?
phones and tablets
what are impact printers?
produce characters by striking the paper
what are the disadvantages of impact papers?
noisy, more expensive, slower
what are the steps of laser printers?
- bitmap image of the page is created
- negative charge is applied to the print drum and then the laser is used to change the polarity on the drum in line with the bitmap image
- drum is exposed to positively charged toner, which is attracted to the negatively charged areas of the drum
- sheet of paper is passed under the drum and toner is transferred onto the paper
- passes to the fusing stage to ensure that the toner sticks to the paper
