Definition
An output device is a piece of hardware that allows data or information to be 'extracted' from a computer.
Examples
- projector
- speaker
- screen/monitor
- printer
- CRT monitor
A cathode-ray tube monitor is an old type of monitor. They are heavy and take up a lot of desk space, so have mainly been place by flat screen monitors and run hot so can cause fires. However they are still used in the design industry as the colour accuracy and brightness are what designer needs.
A thin film transistor has come down in price and have been replacing CRT monitors. They are light in weight and take up little desk space, which has good picture quality like CRT monitor- produce less glare so emits less radiation, but not as good colour accuracy and cannot be used by light pens so they CAD
- Multimedia projectors are used in very large viewing such as presentations, advertising or watching home movies.
- It connects to a computer/DVD player/satellite receiver like an ordinary monitor.
- Projected out through large lens, the image is produced inside the device. Projection happens by using a powerful light source.
- It may be easier to use with bigger groups, but costs a lot to install and run.
- Laser printers are complex printing devices and very expensive to buy, but cheap to use due to the fact that they produce marks on the paper using fine dust(a toner) which is cheap to buy and they can handle large prints
- A single toner cartridge will often last over 5,000 to 10,000 pages of printing. To work, it involves a laser to make a toner stick to required parts of the paper, which is commanded.
- The laser and the toner system allows very fast printing compared to other printer. Laser printers are mainly used in offices because they print very quickly, are cheap to use and are quite quiet.
- 1980's had cheap, quality, colour printing due to inkjets.the printer have a similar print-'head' mechanism to a dot-matrix printer(shown below). The print-'head' goes left and right across the paper.
- However, instead of using pins to hit inky marks onto the paper, the ink-jet squirts tiny droplets of ink onto the surface of the paper. Lots of coloured inks can be used to produce colour printouts.
- This is perfect for photographs. Ink-jet printers are very quiet.
- They have so few moving parts they are also cheap to manufacture and cheap to purchase and the output is high quality but, the output is slow if several copies are needed and the ink is very expensive to buy so the printers are expensive to use- this is how the printer companies make profit
- A dot-matrix printer is named after the pattern/a grid/‘matrix of dots used when creating the printout.
- These dots are formed by tiny pins in the printer’s print 'head' that hit an inked 'ribbon' against the paper, leaving marks.
- As the print head moves along it leaves a pattern of dots behind it for example which can form letters, images.
- Dot-matrix prints poor quality, the printers are noisy- there are much better printing systems available today.
- However, the dot-matrix printers are still used in certain situations:the pins actually hit the paper, several ‘carbon-copies’ can be printed in one go so it makes it easier to print airline tickets which need duplicated pages and they can work in enivroments where laser or inkjets cant work
- Plotters create hard-copy in a very different way to other printers.
- Instead of building up text and images from tiny dots, plotters draw on the paper using a pen.
- The pens are held in an arm which can lift the pen up or down, and which can move across the paper.
- The arm and pen create a drawing just like a human could, but much more accurately and more quickly.Different coloured pens can be used to produce coloured line drawings.
If you want to hear music or sounds from your computer, you will have to attach loudspeakers. They convert electrical signals into sound waves.
Loudspeakers are essential for applications such as music editing,video conferencing, watching movies.
Loudspeakers are essential for applications such as music editing,video conferencing, watching movies.