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 Text  Graphics  Audio  Video  Hard Copy / Soft copy.

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Presentation on theme: " Text  Graphics  Audio  Video  Hard Copy / Soft copy."— Presentation transcript:

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2  Text  Graphics  Audio  Video  Hard Copy / Soft copy

3  Printers  Plotters  Monitors/ VDU

4  As peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies.  Impact printers  Daisy wheel 2. Dot matrix  Non Impact printers  Tonner based (Laser) 2. Liquid ink(Inkjet)

5  Impact printers that use a matrix of small pins to create precise dots.  Dot-matrix printers use a set of closely spaced pins and a ribbon to print letters or other characters on a page.  Dot-matrix printers vary in terms of speed and the number of pins they have. They can run at a speed anywhere between 50 and 500 CPS (Characters Per Second).

6  Daisy-wheel printers operate in much the same fashion as a typewriter.  A hammer strikes a wheel with petals, the "daisy wheel", each petal containing a letter form at its tip. The letter form strikes a ribbon of ink, depositing the ink on the page and thus printing a character. By rotating the daisy wheel, different characters are selected for printing.

7  Line printers, as the name implies, print an entire line of text at a time  In chain printers, also known as train printers, the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, precisely timed hammers strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper.

8  Ink-jets(bubble-jets) printers spray ionized tiny drops of ink onto a page to create an image. This is achieved by using magnetized plates which direct the ink's path onto the paper in the desired pattern.  Ink-jet printers are capable of producing high quality print which almost matches the quality of a laser printer.

9  Laser printers operate by shining a laser beam to produce an image on a drum. The drum is then rolled through toner, and the electrically charged portions of the drum pick up ink. Finally, using a combination of heat and pressure, the ink on the drum is transferred onto the page.  Color laser printers use the same toner-based printing process as black and white ( B/W) laser printers, except that they combine four different toner colors. Color laser printers can also be used as a regular black and white laser printer.

10  That uses heat process to transfer colored dyes or inks to the paper  Photo Printer: A photo printer is a color printer that can produce images that mimic the color range (gamut) and resolution of prints made from photographic film. Many can be used on a standalone basis without a computer, using memory card or USB connector.  Portable Printer: Small light weight and battery powered printer. It uses ink jet, thermal, technology and connects to parallel or USB port  Label / Postage Printer: Small printer that prints on adhesive type material that can be placed on different items like envelopes, packages, CDs, toys etc

11  A plotter is a vector graphics printing device which operates by moving a pen over the surface of paper  large-scale printers that are very accurate at reproducing line drawings.  They are commonly used for technical drawings such as engineering drawings or architectural blueprints

12  Flatbed plotter: A graphics plotter that contains a flat surface that the paper is placed on. The size of this surface (bed) determines the maximum size of the drawing. A graphics output device that draws by moving a pen in both horizontal and vertical directions over a sheet of paper; the overall size of the drawing is limited by the height and width of this bed.  Drum plotter: In drum plotters the pen is moved in a single axis track and the paper itself moves on a cylindrical drum to add the other axis or dimension.

13  Size:  13 to 16 inches, measured diagonally  Color:  Monochrome/ Colored Monitor  Color depth/ Bit Depth: No of colors a monitor can display  Resolution:  No of pixels(picture elements) on screen  More resolution, better image  Refresh rate/ Vertical Scan rate/Vertical frequency:  Speed with which monitor redraws image  Dot pitch  Distance between each pixel on monitor  Smaller dot pitch, better image quality

14  Video Graphics Card: Circuit board that determines:  Resolution  No of colors  Speed with which images appear on monitor screen

15  Video Graphics Array (VGA)  4 BIT color, 16-256 colors at 640 X 840 PIXELS  Super Video Graphics Array (SVGA)  8 bit/ true color, 256colors at 1024 x 768 pixels  15 inch monitors  Extended Graphics Array (XGA)  24 bit/ true color, 16.7 million colors at 1024 x 768 pixels  17-19 inch monitors  Super Extended Graphics Array (SXGA)  1280 x 1024 pixels  19-21 inch monitors  Ultra Extended Graphics Array (UXGA)  1600 x 1200 pixels  21 inch monitors

16  CRT- Cathode Ray tube- the same technology employed by your television- an electron gun scans the screen causing special chemicals called ‘phosphors’ to glow- the gun scans from top to bottom, left to right  Video Adapter- an expansion board or integrated device that renders characters for display in response to commands from the computer- it tells the display device how to draw the graphic

17  Monochrome- two color video- text only with a resolution of 720 x 350  Color Graphics Adapter- CGA- four colors- 320 x 200 resolution for graphics, 640 x 200 for two color  Enhanced Graphics Adapter- EGA- 16 colors- 320 x 200 graphics, 640 x 350 text  Video Graphics Array- VGA- introduced with the IBM AT form factor motherboards- used an analog signal- 256KB of video memory on board- 16 colors at 640 x 480 or 256 colors at 320 x 200  Super Video Graphics Array- introduced by the Video Electronics Standards Association- 65, 536 colors at 640 x 480, 256 colors at 800 x 600 or 16 colors at 1,024 x 768  Extended Graphics Array- IBM’s answer to the SVGA, XGA could only use the MCA expansion bus- it also used interlacing, or scanning every other line on each pass- offered the same resolution options as the SVGA

18  Dot Pitch- the shortest distance between two dots of the same color on the monitor  Measured in millimeters  The lower the number, the sharper the image .28mm is considered average- anything smaller is great  Refresh Rate- vertical scan frequency- how many times in one second does the electron beam redraw the screen? The standard is 60Hz for VGA

19  Most desktop displays use a cathode ray tube (CRT), while portable computing devices such as laptops incorporate liquid crystal display (LCD)  Because of their slimmer design and smaller energy consumption, monitors using LCD technologies are beginning to replace the venerable CRT on many desktops

20 How a CRT monitor works

21  The cathode ray tube is a vacuum tube containing an electron gun (a source of electrons) and a fluorescent screen used to view images  A CRT works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, thereby illuminating the active portions of the screen. /Flat panel

22  These are light weight, takes less space and use less power as compared to CRTs  Doesn’t emit harmful radiations but is expensive then CRT  Technologies of Flat panel Monitors:  Liquid Crystal Display  Glass Plasma

23  LCD displays use two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

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25  Two measures describe the size of your display:  The aspect ratio and the screen size.  Aspect Ratio: Most computer displays, like most televisions, have an aspect ratio of 4:3 This means that the ratio of the width of the display screen to the height is 4 to 3.  Screen Size  How to Measure  Desktop vs. Laptop

26  Scan or Refresh Rate, or vertical scan rate  The time it takes for the electronic beam to fill the screen with lines from top to bottom The number of times that the image on the display is drawn each second. 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. Control flicker You want the refresh rate as high as possible  Standard rate established by the Video Electronics Standards Association (VESA) is 70Hz, or 70 refreshes per second

27  Multiscan  Multiscan monitors support a variety of refresh rates and can support different video cards  Fixed frequency monitors only support a single refresh rate  Interlace features  Interlaced monitors draw a screen in 2 passes, hitting the even lines first, then the odd lines  Non-interlaced monitors draw the entire screen in 1 pass

28  Dot Pitch The distance between adjacent dots on the screen. The smaller the dot pitch, the higher the quality of the image. A high-quality monitor should have a dot pitch of no more than.28mm A display normally can support resolutions that match the physical dot (pixel) size as well as several lesser resolutions. For example, a display with a physical grid of 1280 rows by 1024 columns can obviously support a maximum resolution of 1280x1024 pixels but it usually also supports lower resolutions such as 1024x768, 800x600, and 640x480.

29  Resolution A measure of how many dots on the screen are addressable by software Each addressable location is called a pixel (picture element) Most monitors offer a resolution of 1024 x 768 or higher The video controller card as well as the monitor must be capable of supporting the chosen resolution. Resolutions are set from the Control Panel in Windows 9X

30  Color Depth  The combination of the display modes supported by your graphics adapter and the color capability of your monitor determine how many colors can be displayed.  Bit Depth : The number of bits used to describe a pixel is known as its bit depth. For example: with a 24-bit bit depth, 8 bits are dedicated to each of the three additive primary colors -- red, green and blue. This bit depth is also called true color because it can produce the 10,000,000 discernible colors.

31  A plasma display panel (PDP) is a type of flat panel display common to large TV displays 30 inches (76 cm) or larger.  They are called "plasma" displays because the technology utilizes small cells containing electrically charged ionized gases, or what are in essence chambers more commonly known as fluorescent lamps.

32  Active matrix display: Each pixel is controlled by its own transistor.  An active matrix liquid crystal display (AMLCD) is a type of flat panel display, currently the overwhelming choice of notebook computer manufacturers, due to low weight, very good image quality, wide color gamut and response time.  Passive matrix display / Dual scan monitor: Two transistors control a whole row or column of pixels each at the same time.

33  A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand.

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35 machine for projecting an image onto a screen or other surface. Dictionary.com says a projector is a machine for projecting an image onto a screen or other surface.

36 This is the CRT projector This is the DLP This is an LCD projector

37 LCD (liquid crystal display) projectors work by passing a very strong beam of light through a transparent LCD chip, that has the video playing on it. Advantages Some advantages to LCD projectors is that they are very compact because the LCD chip is so small. Another thing is that they have high contrast and brightness capability and they have a very low power consumption.

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