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Laptops use liquid crystal display (LCD) Monitors using LCD technologies (also called flat panel or flat screen displays) are beginning to replace CRT. ...
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OUTPUTS Intro. to Computer Technologies
Objectives Upon completion of this lesson, students will be able to: • Identify all output plug ins on your computer • Describe the advantages of CRT monitors • Describe the advantages of LCD monitors • Describe the benefits of a Laser Printer
What is an Output Device? • Any device by which a computer transforms its information to the "outside world." • When the device is outside the computer’s main case, we generally call it a peripheral device. • Peripheral means on the edge or outside of an area.
Examples of Output Devices • Monitor • Printer • Modems • Speakers • Projectors • Sound Cards • Video Cards
Monitors • The most frequently used output device. • The display provides instant feedback by showing your text and graphic images as you work or play • Desktop displays use a cathode ray tube (CRT). • Laptops use liquid crystal display (LCD) • Monitors using LCD technologies (also called flat panel or flat screen displays) are beginning to replace CRT.
CRT Refresh Rates • The number of times that the image on the display is drawn each second. • Refresh rates are very important because they control flicker, and you want the refresh rate as high as possible. • Too few cycles per second and you will notice a flickering, which can lead to headaches and eye strain. • If your CRT monitor has a refresh rate of 72 Hertz (Hz), then it cycles through all the pixels from top to bottom 72 times a second.
Cathode Ray Tube (CRT) • Size is measured diagonally (corner to corner). Today monitors are available in sizes 14", 15", 17", 21".
Advantages of CRT • Less Expensive - • Better Color Representation • CRT displays have historically represented colors and different gradations of color more accurately than LCD displays. • Durable • CRT displays are also less fragile and harder to damage.
Advantages of CRT • More Responsive • Fewer problems with ghosting and blurring • Redrew screen image faster than LCD’s • Multiple Resolutions • Ability to change your display's resolution • Viewing Angle
From CRT to LCD • CRT • Bulky & heavy • Using technology that was developed in the 19th century. • LCD • First LCD laptop monitors were very small due to manufacturing costs. • Light, sleek, energy-efficient, have sharp picture.
LCD • Screen Size • Measured diagonally from the inside of the beveled edge. • Measurement does not include the casing as indicated in the image below • LCD 17” = 19” CRT Screen • Widescreen • Computer monitors larger than 40”
Advantages of LCD • Require less power • CRT 100 watts for a 19-inch display. • LCD 45 watts for a 19-inch • LCD’s produce less heat. • Maintains brightness for 25,000 to 50,000 hrs • Smaller and weigh less • Significantly thinner and lighter than a CRT monitor, • Weighing ½ total • Mount an LCD on a wall
Advantages of LCD • Adjustable • Tilt • Height • Swivel • Orientation (horizontal to vertical mode) • Less Eye Strain • Do not produce a flicker or glare • Better job of displaying text compared with CRT displays.
Television and HDTV Integration • Some displays have built-in television tuners that you can use for viewing cable TV on your computer. • You can also find displays that accept S-video input directly from a video device. • Additional features include picture-in-picture or picture-on-picture capability, a remote control and support for high-definition television (HDTV).
Resolution • The number of individual dots of color, known as pixels, contained on a display. • Resolution is affected by a number of factors, including size of the screen. • Expressed by identifying the number of pixels on the horizontal axis (rows) and the number on the vertical axis (columns), such as 800 x 600.
PRINTERS • The job of a printer is to put on paper what you see on your monitor. • How easy this is to do and how successfully it is done determines whether or not you are happy with your printer choice. • Monitor screens and printers do not use the same formatting rules. • In the olden days of computers, the way something looked on the screen could be VERY different from how it would look when printed.
Printers • Early word processors didn't have a way to show what the printed version would look like. • Nowadays we expect What We See Is What You Get, where you see almost exactly what the document will look like in print, while you are still working on it.
Four Types of Printers • Impact • Daisy wheel and Dot matrix. • Direct Thermal • Fax machines and inexpensive / high-portability printers. • Thermal Ink/Color • Ink jet and Bubble jet. • Laser
Ink Jet • Grown in popularity and performance while dropping significantly in price. • Better image quality • Faster than dot-matrix printers • Tendency to smear if page gets wet.
Inkjet Printers • An inkjet printer is any printer that places extremely small droplets of ink onto paper to create an image. • The dots are extremely small, tinier than the diameter of a human hair! • The dots are positioned very precisely, with resolutions of up to 1440x720 dots per inch (dpi). • The dots can have different colors combined together to create photo-quality images.
Laser Printers • Similar to a photocopier • A roller is charged with electricity, then a laser is used to remove the charge from portions of the roller. • Powdered ink (toner) sticks to the parts of the roller that were hit by the laser, and this toner is transferred from the roller to the paper. • Then the ink is baked into the paper using a heater. • Laser printers produce very high quality output and are very fast.
All-in-One • Print, scan and copy from one source • Faxing available on some models • Laser technology for fast print speeds and sharp output • Direct printing from digital cameras on select models • Space-saving design
Photo Quality Printers • Comparable to professional photofinishing • Direct photo printing (select models) from compatible digital cameras • Easy printing for all skill levels • Auto editing features and output sizes (select models)
How Fast? • The speed of a printer is measured in: • cps= characters per second • lpm= lines per minute • ppm= pages per minute • The faster the printing, the more expensive the printer.
Buying a Printer: Consider... • Expense of ink or toner? • How much does a cartridge cost and how many pages will it produce? • Photo inks are more expensive! • Number of cartridges? • One 3-color cartridge or separate black and color cartridges or a cartridge for each color • Output? • What speed is needed? • Is heavy-duty equipment necessary? • Quality of output needed? • Resolution needed • Photo quality? • Location of printer? • How big a footprint can be handled? • Is loudness important?
Video/Sound Cards • Designed to improve upon the onboard video or sound.