3.4 Output Devices...? Flashcards

1
Q

What is a ‘peripheral’?

A

An external device connected to a computer that is used to output information

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2
Q

What is a ‘soft copy’?

A

Data and information that is virtual, data displayed on a monitor.

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3
Q

What is a ‘hard copy’?

A

Data and information that is physical, sound (speakers, headphones) and printed sheets of paper.

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4
Q

What is a ‘footprint’?

A

The physical area (for example on a desk or table) taken up by a peripheral.

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5
Q

What is a ‘pixel’?

A
  • short for ‘picture element’
  • they are illuminated
  • usually can make a combination of red, green and blue
  • many put together make an image
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6
Q

What is the ‘resolution’?

A

The number of pixels in a display.

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7
Q

How many different colours could be represented in a 24-bit display

A

24/3(number of base colours, RGB) = 8
8-bits can hold 255 values
255 x 255 x 255 = over 16 million

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8
Q

Advantages and disadvantages of a flat-panel display…

A

Ad:

  • High resolution
  • No flicker
  • Bright
  • Detailed image/text
  • They can be made at any size, eg for a portable hand held device
  • They have much lower energy consumption

Dis:

  • Easily damaged if dropped
  • A single dead pixel will be very noticeable
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9
Q

What is an ‘LCD’?

A

A Liquid Crystal Display

  • A red, green and blue pixels arranged together make tiny blocks
  • Each block can have the opacity of each colour independently altered, meaning any colour can be made
  • All the blocks have one backlight made from cold cathode fluorescent lamps
  • An LCD is thin and uses low energy
  • Ideal for laptops, tablets, smartphones, sat nav systems
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10
Q

What is an ‘LED Display’?

A

A Light-Emitting Diode Display

  • More advanced than LCD
  • It works in the same way as an LCD except the backlights are LED
  • They are brighter and produce more direct light
  • They are thinner than the cathode fluorescent lamps
  • An LED display has a wider viewing angle than an LCD
  • Sometimes LED Displays have uneven brightness across the display (mostly only on larger displays)
  • A large LED display is lightly to use more power than an LCD
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11
Q

What is an LCD Projector work?

A
  • There are three LCD panels R, G and B

- This type of projector has better colour contrast

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12
Q

How does a DLP Projector work?

A
  • It uses millions of tiny mirrors to reflect light towards the projector lens
  • This creates an image with better colour reproduction but less contrast and brightness
  • Smaller than LCD projectors, DLP can be made portable
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13
Q

How does an ‘inkjet’ printer work?

A
  • Uses ink sprayed through microscopic nozzles
  • A colour inkjet printer has four times as many nozzles, one for each colour, CMYK, Cyan, Magenta, Yellow and Key (black)
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14
Q

Advantages and disadvantages of an inkjet printer…

A

Ad:

  • Cheaper to buy than other printer(s) [technologies] (to buy the hardware)
  • With photographic paper the image quality is excellent
  • Ideal for use in the home

Dis:

  • Expensive to run as they use a lot of ink
  • Printing on normal paper results in poor quality as the liquid ink can bleed
  • Difficult to print on both sides of the paper
  • They are slow at printing
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15
Q

How does a ‘laser’ printer work?

A
  • Uses coloured powder (toner) from a toner cartridge, of which there will be 4, CMYK
  • It uses a laser to create static on certain areas of the page (areas that require ink to print the desired image or text) then the toner is scattered onto the page and attracted to the static areas, which stick it to the page
  • Then a fusing element is used to make sure that the toner is bonded to the page
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16
Q

Advantages and disadvantages of a laser printer…

A

Ad:

  • They are cheap to run
  • Printed text quality is excellent
  • Very quick at printing, ideal for large numbers of documents, eg in a school
  • They are suited to duplex printing (both sides) generally halving paper costs

Dis:

  • Expensive to buy as that is the nature of laser technology
  • Image printing on photographic paper is not as good as it it on an inkjet
  • Generally have a larger footprint than other printers
17
Q

How does a ‘3D’ printer work?

A
  • Requires a 3D object to be drawn in CAD or an object be scanned by a 3D scanner
  • The digital object is then split into lots of thin horizontal layers
  • Starting at the bottom the printer uses a plastic thread that it melts and then solidifies to print each layer
18
Q

Advantages and disadvantages of a 3D printer…

A

Ad:

  • Easy way to produce bespoke or prototype products
  • Any shape can be made
  • An item can be edited and re-printed as many times as the user wants without having to manufacture parts, saving time
  • Designs can be easily shared as a digital file

Dis:

  • It is expensive
  • 3D printed plastic models may be considerably less durable than manufactured models
  • ‘Dangerous’ items could be printed
  • Easy to create copyright issues by printing someone else’s design
19
Q

What is ‘CAM’?

A
  • Computer Aided manufacturing
  • Computers and machinery work together to manufacture products
  • Additional software then takes the 3D CAD designs and uses them to control machinery
  • The CAM software controls and monitors the machinery to ensure the product is manufactured correctly
20
Q

What is ‘CNC’?

A
  • Computer Numerical Control
  • The name of the method used by CAM to control machinery
  • There are 2D and 3D versions
21
Q

Advantages and disadvantages of CAD…

A

Ad:

  • Products can be manufactured/reproduced at a much higher accuracy
  • Higher production quality can be easily maintained
  • It allows the user to produce high quality bespoke items and prototypes

Dis:

  • Training is required to use it
  • If only one of each product design is being produced then it is a more expensive method
  • The initial costs introducing CAM to products manufacture is very expensive
22
Q

What is a ‘DAC’?

A
  • Digital-Analogue Converter

- For sound to be outputted through speakers or headphones, the signal has to be converted from digital to analogue

23
Q

Advantages and disadvantages of speakers…

A

Ad:

  • Another method of giving information to the user
  • They can help disabled users
  • Can be used to send messages/alerts/warnings in a public space where everyone is not looking in one direction

Dis:

  • Built-in device speakers are often poor quality
  • Sound produced may disturb other users
  • A sound card with a DAC is required