Information Technology

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David Holland
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1 Information Technology Output Devices Lecture 6 Presented by Miss N. Nembhard

2 Output Devices Receives an electrical signal and produces data or information. The purpose of an output device is to translate data and information from electrical impulses (digital) to human readable format.

3 The Monitor An output device which is necessary for the computer to display an output to the user. The video display Adapter (video card) on the motherboard allows information to leave the processor and appear on the monitor.

4 Terms Associated with the Monitor Soft copy - copy of a file shown on the screen. It is intangible. Pixel (Picture Element) - A single point (a dot) in an electronic image. The greater the number of pixels, the better the quality of the image.

5 Screen Clarity Screen clarity depends on three things: Resolution - Defines the clarity of an image and is specified as the number of dots per inch (dpi). Normally measured by the number of pixels that can be displayed. Dot Pitch - Amount of space between pixels Refresh Rate - Number of times per seconds that the pixels are recharged so that their glow remains bright.

6 The Printer An output device that produces tangible copies or hard copies. Hard copy -A tangible copy of a document produced by the printer e.g. flyer, letter, book, a card etc.

7 Categories of Printers There are two main categories of printers: Impact - the printing mechanism makes physical contact with the paper Non-Impact - No physical contact between the printing mechanism and the paper.

8 Advantages of Impact Printers Produces carbon copies of information being printed. Inexpensive Maintenance is inexpensive Uses ink ribbons which are inexpensive

9 Disadvantages of Impact Printers They are relatively slow Draft quality is low Ink ribbons have short lives Noisy

10 Advantages of Non-impact Printers Produce high quality and high speed output Almost noiseless uses toner or ink cartridges, which are longer lasting

11 Disadvantages of Non-Impact Printers Printers are usually expensive Maintenance is also expensive Toner is relatively expensive

12 Types of Printers Dot Matrix: Impact printer Inkjet: Non-Impact printer Laser: Non-Impact printer

13 Plotter Output device used to produce high quality drawings (images) and large hard copies e.g. posters. Chosen over printers when high quality graphics and making large clear posters.

14 Plotters continued Have built in microprocessors that converts characters and instructions into a series of coordinates, which the plotter then plots. Produces high resolution images Used by engineers, graphic designers, architects.

15 Speakers Sound cards code audio signals into signals which can be used by the speaker, which in turn amplifies them. Sub woofers - Speaker system that can be attached to your PC and speakers to enhance your sound effects.

16 Computer Output on Microfilm Computer output on film rather than on paper. Stores images on plastic films. Images are held in a much reduced format.

17 Microfilm Reels of films used to store data or images. Primarily used to store for preserving journals and news papers and hold hundreds of prints on one film.

18 Microfiche Flat individual sheets of film. Primarily used to preserve government document and college catalogues. A special reader is needed to view the pages stored.

19 Multimedia Projector Works with a variety of media, e.g. computer, camera, printer and the scanner. It projects and magnifies images on a large white screen normally mounted on a wall some distance from the computer.

20 Activity 1. Explain the following terms associated with the monitor: a. Resolution b. Pixel c. Dot Pitch d. Refresh Rate 2. Identify the two main types of printers 3. Give an example of each of the two types of printers you identified above. 4. Differentiate between the terms : hardcopy and softcopy.

Sir Sadiq s computer notes for class IX. Chapter no 3. Input/Output Devices

Sir Sadiq s computer notes for class IX. Chapter no 3. Input/Output Devices 12 Q: What are Input Devices? Ans: Input Devices: Input devices are physical equipment that read or translate data consisting of alphabets, numbers or other symbols into electronic impulses, which can