Output Devices of Computer

1. Output Devices of Computer www.assignmentpoint.com

2. OUTPUT • Printer • Visual Display Units • Graph plotters • Speakers • Arm robot www.assignmentpoint.com

3. Printers A computer printer, or more commonly a printer, produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local computer peripherals, and are attached by a printer cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time. www.assignmentpoint.com Click here to Types of printers

4. Type of printers • Laser printer • Inkjet printers • Dot-matrix printer www.assignmentpoint.com

5. Laser printer Disadvantages: Non-color laser printers are more expensive than ink-jet printers (but the difference is narrowing). Color laser printers are considerably more expensive. (but their speed and high quality output means they are becoming more popular). Advantages: They are quiet and fast and produce high quality printouts. Running cost are low because although toner cartridges are expensive to replace, they last a long time. Disadvantages: Non-color laser printers are more expensive than ink-jet printers (but the difference is narrowing). Color laser printers are considerably more expensive. (but their speed and high quality output means they are becoming more popular). Advantages: They are quiet and fast and produce high quality printouts. Running cost are low because although toner cartridges are expensive to replace, they last a long time. A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. Like photocopiers, laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. Like photocopiers, laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor www.assignmentpoint.com

6. Inkjet printers How it works: The print head contains tiny nozzles through which different coloured inks can be sprayed onto the paper to form the characters or the graphic images. The ink is forced out by heat or by tiny piezoelectric crystals which change shape when an electric current is applied across them. Disadvantages: The ink cartridges can be expensive so running costs can be high. The printing speed is slow compared to a laser printer.  Advantages: These printers are relatively inexpensive and produce high quality black and white or colour printing.  www.assignmentpoint.com

7. Dot-matrix printer Disadvantages: The printing quality is low - these printers produce low to medium quality black and white printing and can only print low resolution graphics. Because of the impact of the pins against the paper, these printers can be quite noisy. Advantages: The purchase cost is low and the running costs are very low. They can print fairly quickly, particularly if you remember that multiple copies are being printed in one print run. They are robust and can operate in harsh environments. If several sheets of self-carbonating paper are placed into the printer then the impact will produce multiple copies. How it works:  This has a print head that travels across the paper. The head has a set of pins which are pushed out to form the shape of each character The pins hit an ink ribbon against the paper as the print head moves along. An animation showing how head of a 21 pin dot-matrix printer moves across the paper, firing the pins that strike the ink against the paper. www.assignmentpoint.com

8. VISUAL DISPLAY UNIT • A monitor is a peripheral device which displays computer output on a screen. • Screen output is referred to as soft copy. • Types of monitors: • Cathode-ray tube (CRT) • Liquid Crystal Display (LCD or flat-panel) www.assignmentpoint.com

9. Cathode-ray tube (CRT) • Resemble televisions • Use picture tube technology • Less expensive than a LCD monitor • Take up more desk space and use more energy than LCD monitors www.assignmentpoint.com

10. Liquid Crystal Display (LCD) • Cells sandwiched between two transparent layers form images • Used for notebook computers, PDAs, cellular phones, and personal computers • More expensive than a CRT monitor • Take up less desk space and use less energy than CRT monitors • Types of LCD monitors: • Passive-matrix LCD • Active-matrix LCD • Gas plasma display • Field emission display www.assignmentpoint.com

11. Monitor Specifications • Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21) • Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200) • Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz) www.assignmentpoint.com

12. Graph plotters the flat-bed plotter uses high precision motors  to draw on paper with colored ink pens. The motors move an arm across the paper in the ‘x’ direction and a pen unit up and down the arm in the ‘y’ direction. An electromagnet lifts and drops the pen onto the paper. Plotters are often used in science and engineering applications for drawing building plans, printed circuit boards and machine parts. They are fast and accurate but relatively expensive compared to printers. They can produce far larger printouts than standard printers, up to the size of a small room. Braille printer - by converting text into the Braille code, this printer produces patterns of raised dots on paper for use by the blind. www.assignmentpoint.com

13. Speakers Computer speakers, or multimedia speakers, are external speakers, commonly equipped with a low-power internal amplifier. The standard audio connection is a 3.5mm (1/8 inch) stereo jack plug often color-coded lime green (following the PC 99 standard) for computer sound cards. A few use an RCA connector for input. There are also USB speakers which are powered from the 5 volts at 200 milliamps provided by the USB port, allowing about 1-watt of output power. www.assignmentpoint.com

14. Arm robot A arm robot is a robot manipulator, usually programmable, with similar functions to a human arm. The links of such a manipulator are connected by joints allowing either rotational motion (such as in an articulated robot) or translational (linear) displacement. [The business end of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hand. The end effector can be designed to perform any desired task such as welding, gripping, spinning etc., depending on the application. For example robot arms in automotive assembly lines perform a variety of tasks such as welding and parts rotation and placement during assembly. www.assignmentpoint.com