Chapter 5 - Output devices

any piece of computer hardware equiptment used to communicate the results of data processing carried out by a computer the device converts the computer’s digital information into a human-readable form

laser, inkjet, dot matrix

rely on positive and negative charges on the print drum and paper; toner sticks to the paper in only certain areas and is permanently fixed using a fuser

rely on liquid ink system which sprays ink onto the paper line by line as the paper advances; uses either thermal bubble or piezoelectric technologies

use a matrix of pins that strike an inked ribbon (either black or up to 4 coloured) to produce characters in a matrix on the paper

very high quality of printing relatively inexpensive to buy printer large toner cartridges and large paper trays very fast printing of multiple documents

can be expensive to maintain produce health hazards such as ozone or toner particles in the air

high quality of printing very suitable for printing photos inexpensive to buy printer

ink is expensive to buy and runs out quickly usually have small paper trays can be noisy compared to laser printer

not adversely affected by damp or dusty/dirty atmospheres allows use of multi-part stationery (carbon copies) allows use of continuous/fan-folded stationary

relatively expensive to buy printer poor print quality very noisy and slow at printing

produce actual solid objects which work built up in the printer in a number of very thin layers of varying materials

the use of a binder (a type of glue) to form the solid layers

they build up objects layer by layer

making prosthetic limbs manufacture of aerospace parts fashion and art making parts no longer in production by conventional manufactering

machines used to cut into materials to form 3D objects and are controlled by computers and software such as CAD materials include; glass, crystal, metal, wood, polymers

loudspeakers convert analogue voltages into sound if the output is from a computer, the digital signals are first converted into analogue voltages using a DAC

the rate at which the DAC can translate the digital output into analogue voltages usually 44 100 samples/second for a 16 bit system

backlit using LEDs rather than cold cathode fluorescent lamps (CCFLs)`

the LCD does not produce its own light

reach max brightness faster make whiter light brighter colour = improved colour definition much thinner and lighter last almost indefinitely consume much less power

organic light emitting diodes produce their own light and do not need back-lighting

very thin and flexible screens much brighter light than LEDs don’t require any form of backlighting much larger field of view

digital light projectors (DLP) LCD projectors