Output Units

Output devices: These are peripheral equipment that allows data from the computer to be converted to human readable forms.

Allows the conversion of "computer language" into "human language"

Two types of Output Device Classifications:

i. Hard Copy

· Printer

· Plotter

· Microfilm

· Film and VHS/video

ii. Soft Copy

· Video Display Units (VDU's or "screens" or "monitors")

· Voice

· Sound Cards

· Another computer

· Others?????

Types of printers:

Impact printers

Impact a solid image of a character onto an inked ribbon up against the paper.

i. Daisy wheel, band, chain and drum printers

(Old technology)

ii. Dot Matrix:

Line of solid pins that moves across the page

9 and 24 pin printers

Can print graphics

Non-impact printers

No physical contact between paper and printing device

Dot matrix concept used to form characters

i. Laser

ii. Ink jet

iii. Thermal

Types of Video Display Units (VDU's):

Also called screens, terminals, and monitors.

Types of screens:

Most common screen
cathode ray tube (CRT)

Another screen
liquid crystal display(LCD)

Gas Plasma

Most CRT screens use a technology called raster-scan technology.

The electron gun scans left to right/top to bottom across the screen grid.

Monochrome Monitor

Color

Monitor