Page 44 - 4130

darker. Other types of flat panel technology exist (such as plasma
displays) but LCDs are most commonly used in computers,
especially laptops. Flat panel displays are much lighter and less
bulky than CRT monitors, and they consume much less power.
Printers
For hardcopy (printed) output, you need some kind of printer
attached to your computer (or available over a network). The most
common types of printers for home systems is the color ink jet
printer and laser printer. Ink jet printers form the image on the page
by spraying tiny droplets of ink from the print head. The printer
needs several colors of ink (cyan, yellow, magenta, and black) to
make color images.
A laser printer produces good quality images by the same
technology that photocopiers use. A drum coated with photosensitive
material is charged, then an image is written onto it by a laser (or
LEDs) which makes those areas lose the charge. The drum then rolls
through toner (tiny plastic particles of pigment) that is attracted to the
charged areas of the drum. The toner is then deposited onto the
paper, and then fused into the paper with heat.
Multi-function printers are available that not only operate as a
computer printer, but also include the hardware needed to be a
scanner, photocopier, and FAX machine as well.
Sound Output
Computers also produce sound output, ranging from simple
beeps alerting the user, to impressive game sound effects, to concert
quality music. The circuitry to produce sound may be included on the
motherboard, but high quality audio output from a PC usually
requires a sound card in one of the expansion slots, connected to a set
of good quality external speakers or headphones.
Multimedia is a term describing computer output that includes
sound, text, graphics, movies, and animation. A sound card is an
example of a multimedia output device (as is a monitor that can
display graphics).

42