Excellence Publication Co. Ltd. Volume 1 2.41 Volume 1.

Excellence Publication Co. Ltd.Volume 1 2.4 1

Volume 1Volume 1


A. MonitorsA. Monitors

used to display text, graphics, animation and video

There are two types of monitors:

1. Cathode Ray Tube (CRT) 1. Cathode Ray Tube (CRT) MonitorsMonitors


MonitorMonitor

Monochrome CRT

Gray-scale CRT

Colour CRT

Colour Colour CapabilityCapability

One background colour and one foreground colour, e.g. Black and White

Different shades of gray

16 to more than one million different colours.

A comparison of different CRT monitorsA comparison of different CRT monitors


2. Liquid Crystal Displays (LCDs)2. Liquid Crystal Displays (LCDs)

LCD is much thinner than the CRT monitor.

Consumes much less power because it works on the principle of blocking light rather than emitting it.


Tips on buying MonitorsTips on buying Monitors

Screen size is measured in diagonal inchesScreen size is measured in diagonal inches

1. Identify your resolution needs.2. Know the size of monitors.3. Check the refresh rate.4. Match your graphics card.


B. LoudspeakersB. Loudspeakers used to reproduce sounds

How loudspeakers workHow loudspeakers work

Voicecoil

Vibrates the diaphragm

Vibrates the air

Produce a sound wave


C. PrintersC. Printers used to print characters or images on paper

1. Daisy-wheel Printer1. Daisy-wheel Printer There are different types of printers:

use hammers to press plastic or metal wheels against ribbons

Noisy

Slow speed

cannot print graphics


3. Thermal Printer3. Thermal Printer

push heated pins against heat-sensitive paper

print receipts

2. Line Printer2. Line Printer

make character chains or pins and print an entire line at one time

produce low quality text


4. Dot-matrix Printer4. Dot-matrix Printer

Strike pins against ink ribbons

print invoices in carbon paper and continuous form

5. Ink-jet Printer5. Ink-jet Printer Spray ink at paper

Fast speed Non-impact

Better print quality


6. Laser Printer6. Laser Printer

Use lasers to produce images on drums and then print the images

Quiet

Support an almost unlimited variety of fonts

Can print both characters and images in high quality


D. PlottersD. Plotters

used to draw images on paper with ink pens

There are two types of potters:There are two types of potters:

Drum Plotter Flatbed PlotterDrum Plotter Flatbed Plotter paper is wrapped around

drums with pins feeds paper is placed on flat

surface paper is moved back and

forth for one direction of plot

the size of the surface determines the maximum drawing size


A Comparison between a Plotter and a PrinterA Comparison between a Plotter and a Printer

Plotter PrinterPlotter Printer draw real continuous

lines to provide infinite resolution

only simulate lines by printing closely spaced dots

usually used to produce drawings of large sizes

usually used to produce drawings of small sizes

suitable for engineering and architectural drawings

suitable for home and general office users


State the reasons why many State the reasons why many

customers prefer LCD to CRT customers prefer LCD to CRT

monitor nowadays. And discuss monitor nowadays. And discuss

whether LCD would replace LRT whether LCD would replace LRT

monitors in the coming five years.monitors in the coming five years.


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