3.4 Output Devices...? Flashcards
What is a ‘peripheral’?
An external device connected to a computer that is used to output information
What is a ‘soft copy’?
Data and information that is virtual, data displayed on a monitor.
What is a ‘hard copy’?
Data and information that is physical, sound (speakers, headphones) and printed sheets of paper.
What is a ‘footprint’?
The physical area (for example on a desk or table) taken up by a peripheral.
What is a ‘pixel’?
- short for ‘picture element’
- they are illuminated
- usually can make a combination of red, green and blue
- many put together make an image
What is the ‘resolution’?
The number of pixels in a display.
How many different colours could be represented in a 24-bit display
24/3(number of base colours, RGB) = 8
8-bits can hold 255 values
255 x 255 x 255 = over 16 million
Advantages and disadvantages of a flat-panel display…
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
What is an ‘LCD’?
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
What is an ‘LED Display’?
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
What is an LCD Projector work?
- There are three LCD panels R, G and B
- This type of projector has better colour contrast
How does a DLP Projector work?
- 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
How does an ‘inkjet’ printer work?
- 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)
Advantages and disadvantages of an inkjet printer…
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
How does a ‘laser’ printer work?
- 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