business studies stage i computer applicationsslide 1 output devices output devices are all part of...
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Business Studies Stage I Computer Applications Slide 1
Output Devices
Output Devices are all part of the Hardware of a computer system
Output Devices are about seeing the results of your work!
Business Studies Stage I Computer Applications Slide 2
Some Output Devices
Video Monitor
Sound
ControllingOther Machines
Paper
Business Studies Stage I Computer Applications Slide 3
Types of Output
• Soft Copy• Hard Copy• Communications
Channel
Business Studies Stage I Computer Applications Slide 4
Screen Output – Soft Copy
• Video Monitor– Also called Video
Display Terminal (VDT)– Image exists in video
memory—VRAM– Monitor size is
measured diagonally across the screen
Business Studies Stage I Computer Applications Slide 5
• Images are made up ofdots called pixels forpicture elements
• The number of pixels determines the clarity of the picture on the screen
• More pixels = higher resolution = clearer picture
Pixels
Business Studies Stage I Computer Applications Slide 6
Color Depth (Bit Depth)• This means the amount of information
stored in each pixel about what is being shown on the monitor– Monochrome (1 bit of information per
pixel)• This can only be black or white
– Gray-scale (8 bits of information per pixel)• This can show more shades of grey
– True color (24 or 32 bits of information per pixel)
• This can realistically reproduce a photograph on the screen that looks very close to the original
Business Studies Stage I Computer Applications Slide 7
Examples of Color Depth
1-bit depth 4-bit depth
8-bit depth 16-bit depth
The greater the color depth the more colours that can be represented on the screen
Business Studies Stage I Computer Applications Slide 8
CRT (cathode ray tube)
LCD (liquid crystal display)
Classes of Monitors
Business Studies Stage I Computer Applications Slide 9
• A CRT is a television-style monitor
• Its features include:– Clear image– Quick response time– Low cost– Very popular
CRT (Cathode Ray Tube)
Business Studies Stage I Computer Applications Slide 10
Features of CRT Displays
• Display text and graphics• Monitors differ in resolution• Standards
– SVGA – 1024 x 768, 1208 x 1024 and 1600 x 1200
– XGA – has same resolutions but supports more colours
• Screen sizes vary from 15” to 21”
Business Studies Stage I Computer Applications Slide 11
• LCDs comprise flat-panel monitors• Found on watches, calculators,
digital cameras and notebook computers– Lighter weight– Crisp,clear images– Extra viewing area for same size– More expensive to buy– Consume less power
LCD (Liquid Crystal Display)
Business Studies Stage I Computer Applications Slide 12
Paper Output – Hard Copy
• A printer is a device that produces output on paper
• Most printers today can produce both text and graphics
• Two types of printers:– Impact printers– Non-impact printers
Business Studies Stage I Computer Applications Slide 13
Impact Printers
• There is some physical contact with the paper to produce the image ie physically striking the paper
• Types– Line printers– Dot matrix printers
Business Studies Stage I Computer Applications Slide 14
• Line printers– Used by mainframes for
jobs that need a large volume of printing
– Limited characters available– Print an entire line at a time– Cheap to run– Not high quality
Line Printer
Business Studies Stage I Computer Applications Slide 15
Dot Matrix Printer
• Have a printhead made up of columns of pins– The pins form characters and images
as patterns of dots produced when the pins strike the paper
– Reasonable quality text and graphics– Inexpensive to buy and run– Noisy
Business Studies Stage I Computer Applications Slide 16
Non-Impact Printers
• Laser Printers• Ink-jet printers• Bubble-jet printers
Business Studies Stage I Computer Applications Slide 17
Laser Printers
• Laser printers– Image transferred to
paper with a laser beam•Faster and more expensive
than dot-matrix•High-resolution output•Expensive to buy•Quite expensive to run
Business Studies Stage I Computer Applications Slide 18
Ink-Jet Printers
• Ink-jet– Dots of ink are sprayed onto the
paper to form the image– Reasonably high quality– Available in colour or B/W– Speed measured in pages per
minute– Reasonably priced– Expensive to run
Business Studies Stage I Computer Applications Slide 19
Plotters• Used by graphic
designers/architects– Image transferred to paper
with ink pens– Very high resolution – Excellent for scientific and
engineering applications
Business Studies Stage I Computer Applications Slide 20
Printing Terms
• Dots per inch (dpi)• Pages per minute (ppm)• Characters per second (cps)• Laser printers – 50 ppm• Ink-jet printers – 12 ppm
Business Studies Stage I Computer Applications Slide 21
Output You Can Hear
• Synthesizers can beused to generate music and sounds
• Many computershave synthesizers
• Sound cards havebuilt-in synthesizers
Business Studies Stage I Computer Applications Slide 22
• By turning bit information into movements (robots) or measurements (sensors), machines can control other machines:– Automated factory equipment– Telephone switchboards– Robot arms– Spacecraft
Machines Controlling Other Machines