Output Devices

Disadvantages of impact computers

-noisy -does not usually print acceptable graphics

CRT

Cathode Ray Tube

Examples of impact printers

Daisy Wheel Printer Dot Matrix Printer Line Printer

LCD

Liquid Crystal Display

LED

Liquid Emitting Diode

Hard Copy

Permanent. It is printed for you to review away from the computer.

PIXEL

Picture Elements

Soft Copy

Temporary. Includes output from a computer monitor, audio, and electrical signals.

NON-IMPACT PRINTERS

They do NOT involve striking paper. They produce an image by producing a stream of ink directly on to the page use.

IMPACT PRINTER

They have a print head that strikes an inked ribbon against the paper. They typically print one character at a time

RESOLUTION

This determines how clear and vivid the output on the screen can be.

VDU

Visual Display Unit

microfiche

a flat piece of film containing microphotographs of the pages of a newspaper, catalog, or other document.

Microfilm

output is printed on a roll of computer film (machine readable)

Advantages of non impact printers

quieter and may produce better quality images.

Output

to produce the results of processed data

Advantage of impact computers

useful for printing multiple copies using carbon paper

plotter

uses coloured pens or toner to draw an image on paper.