Output devices - advantages and disadvantages of each

Question 1

What are output devices?

Answer 1

Hardware devices that allow data to be output from a computer
Some hold data temporarily e.g. a monitor
Some produce permanent output in the form of a hardcopy e.g. a printer

Question 2

CRT Monitors

Answer 2

Advantages
Produce higher quality images than TFT monitors
Angle of viewing is better than a TFT monitor
They work with light pens in CAD and CAM applications (Computer Aided Design/Manufacturing)
Disadvantages
Tend to be heavy, weight hazard if not supported properly
Run very hot, can cause fires if left unattended – especially if they are old
Consume more power than TFT monitors
They can flicker, this leads to headaches and eyesight problems with prolonged use

Question 3

TFT Monitors

Answer 3

Advantages
Lightweight, so no weight hazards like CRT monitors
Less glare produced than in CRT monitors; also emit less radiation
Consume much less power and generate less heat than CRT monitors
Disadvantages
Angle of viewing is critical, image appears unclear if viewed slightly from the side
The definition is sometimes not as good as CRT monitors
They cannot yet be used with light pens, so cannot be used in CAD

Question 4

Laser Printers

Answer 4

Advantages
Printing is fast for high volumes, slightly faster than inkjet if only a few pages are to be printed
Can handle very large print jobs
Quality is consistently high
Toner cartridges last for a long time; laser printers can be a cost effective option if colour outputs are not required
Disadvantages
Expensive to buy
Only really fast if several copies are being made
Colour laser printers tend to be expensive to run since four cartridges are needed as well as diffuser kits, etc.
Produce ozone and volatile organic compounds because of their printing method and type of toner/ink
used

Question 5

Inkjet Printers

Answer 5

Advantages
High quality output
Cheaper to buy than laser printers
Very lightweight and take up little space (small footprint)
Do not produce ozone and volatile organic compounds, unlike laser printers
Disadvantages
Output is slow if several copies needed – there is little buffer capacity to store the pages
The ink cartridges run out too quickly to be used for large print jobs
Printing can smudge if the user is not careful
Can be expensive to run if they are used a lot – original ink cartridges are expensive

Question 6

3D Inkjet Printers
A new type of printer that produces solid 3D models using modified inkjet technology called tomography
Very thin layers of fine powder (plaster, resin, starch) are bonded together as a 3D model is slowly built up
Items produced are known as prototypes

Answer 6

Advantages
Save a lot of money, other methods of making prototypes are very time consuming and expensive
The powders used can often be ground up and reused
Physical scale models are produced with working parts, which gives a better idea of how the end product will look
Disadvantages
Expensive to buy
Slow at producing their output
End product is sometimes a little rough, often further work needs to be done

Question 7

Dot Matrix Printers
A type of impact printer
A print head made up of a matrix of pins presses against an inked ribbon

Answer 7

Advantages
Can be used in environments which would be a problem for laser and inkjet printers – dusty, dirty or moist atmospheres
Carbon copies or multi-part outputs can be produced
Very cheap to run and maintain
Easy to use if continuous stationary is required e.g. long print jobs such as wage slips
Disadvantages
Very noisy – not good in an office environment
Cost more than an inkjet printer to buy
Very slow
Printing is of poor quality

Question 8

Graph Plotters

Used to produce large drawings e.g. blueprints of buildings; are often used with CAD applications

Answer 8

Advantages
Can produce huge printouts
Print quality is extremely high
Disadvantages
Slow in operation
Expensive to buy and maintain

Question 9

Speakers

Answer 9

Advantages
Usually long lasting and durable (if operated within their intended power levels)
Often provided with the computer/laptop although these may not be the best quality
Disadvantages
Can take up a lot of desk space, compared to headphones
Can distract people around you, everyone can hear what you are playing
May not be able to hear the full sound spectrum, this requires multiple speakers

Question 10

Multimedia Projectors
Used for training presentations ( allows the whole audience to see the images from a computer)
Also used for advertising presentations (shown at exhibitions, shopping malls etc.)
Home cinema systems (projecting the images from a DVD or television) use multimedia projectors

Answer 10

Advantages
Enables many people to see a presentation rather than all of them crowded around a small computer
screen
Avoids the need for several networked computers e.g. when looking at a video clip on the internet, everybody can see the video on the large screen rather than logging on to a number of computers
Disadvantages
Images can sometimes be fuzzy
Expensive to buy
Setting up projectors can be a little difficult

Question 11

Control Devices: a type of output device

Used to control processes when combined with sensor input devices

Answer 11

Actuators:
Transducers that are used to take signals from a computer and convert them into some form of motion e.g. operating motors, pumps, switches and valves
Digital signals are sent from the computer to an actuator
Motors:
Turned on or off by the actuator
Buzzers:
Switched on or off by the actuator
Lights:
The actuator is connected to the switch that turns the lights on or off
Heaters:
Actuators are connected to switches which turn the heater on or off