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Input Output devices
- 1. Input and Output DevicesInput and Output Devices ByBy Dr. Pravin H. GhosekarDr. Pravin H. Ghosekar M.Sc.(C/S), MCM, DBM, M.Phil(IT), M.Phil(Comm), MBA, BJ. Ph.D.M.Sc.(C/S), MCM, DBM, M.Phil(IT), M.Phil(Comm), MBA, BJ. Ph.D. HOD Computer DepartmentHOD Computer Department Dhanwate National CollegeDhanwate National College NagpurNagpur 08/10/201008/10/2010
- 2. Input Devices • An input device is an electromechanical device that accepts data from outside world and translates them into a form a computer can interpret. • The I/O devices that provide a means of communication between the computer and the outside world are known as peripheral devices
- 3. Keyboard • Keyboard is a primary input device. • It allows input into the computer system by pressing a set of keys available on a board connected to the computer system • The standard keyboard has 101 keys Keyboard has following keys : 1. Alphanumeric Keys 2. Numeric Keypad 3. Function keys 4. Arrow keys 5. Special keys (Shift,Alt,Ctrl,,Enter, etc)
- 4. Mouse • A mouse is a small device that the users can use to point to a particular place on a screen or to select one or more icons and execute commands . • Mouse contains two or three buttons on the top. When user moves the mouse on the flat surface; the cursor also moves in the same direction on the screen. • Some mouse also having scroll wheel on the top of the mouse which is used to scroll the screen Mouse are of three different types as follows : 1. Mechanical Mouse 2. Optomechanical mouse 3. Optical mouse Pointing Devices/ Direct Entry Devices / Point-and-draw devices :
- 5. Trackball • The trackball is a pointing device that is similar to inverted mouse. • It consists of a ball fitted in the small external box or on the keyboard in some portable computers. Pointing Devices/ Direct Entry Devices / Point-and-draw devices : JoyStick • . It is a vertical stick that moves the graphic cursor in the direction as the stick moves. • It consists of a small, vertical lever mounted on a base that is used to steer (move) the screen cursor on monitor. • Joysticks are generally used to control video games,
- 6. Light Pen • A light pen is a small pen-shaped device, which contain light sensors and is activated by pressing the pen against the display screen. • The sensor is the scanning beam that helps in locating the pen’s position (X and Y coordinates on the screen). Pointing Devices/ Direct Entry Devices / Point-and-draw devices : Touch Screen • Touchscreens panels have the ability to display and receive information on the same screen. • It is a display which can detect the presence and location of a touch within the display area. • Touch screens can sense finger/hand or the stylus (writing utensil similar to ball point pen) or any other object. • It enables us to interact with; what is displayed directly on the screen, rather than indirectly with a mouse or touchpad.
- 7. Scanner • Scanning devices are input devices used for direct data entry from the source document into the computer system. • Scanners facilitate the capturing of information and storing it in a graphical format • It consist of two components, one to illuminate the page so that the optical image can be captured and the other to convert the graphical image into a digital format for storing so that we can process it. • Scanner are of two types 1. Hand- Held Scanner 2. Flat-bed Scanner Scanning Devices
- 8. Optical Character Recognition (OCR) • OCR is the mechanical or electronic translation of images of handwritten, typewritten or printed text into machine- editable text. • This device is work similar to the scanner; it takes inputs from the printed matter or any other object. Scanning Devices
- 9. MICR (Magnetic Ink Character Recognition) • MICR devices are used by the banking industry to read the account numbers on cheques directly and subsequently perform the necessary processing. Scanning Devices Magnetic Ink Characters
- 10. Optical Bar Code reader (OBR) • A barcode reader (or barcode scanner) is an electronic device for reading printed barcodes. • Data coded in the form of small vertical lines forms the basis of bar coding. Alphanumeric data is represented using adjacent vertical lines called Bar codes. • A barcode reader uses laser beam technology Scanning Devices
- 11. Optical Mark reader (OMR) • OMR is an automatic optical sensing of marks recorded on a data medium. • In this method special preprinted forms are designed with boxes which can be marked with a dark pencil or ink. Scanning Devices This is generally used as 1) Objective type answer papers 2) Market surveys, population surveys etc. 3) Order forms containing a small choice of items. 4) Survey forms which is having objective question and number of forms.
- 12. Microphone Voice Recognition Devices Vision Input devices / Imaging & Video Input Devices : •Web/Digital Camera Video Camera :
- 13. Output Devices • An output device is an electromechanical device that accepts data from the computer and translates into a form that can be understood by the outside world. • Output produced on display units or speech output that cannot be touched and it is known as softcopy output while output produced on paper or material that can be touched, is known as hardcopy output.
- 14. Monitor • Monitor is a primary output device. The monitor also known as Visual Display Unit (VDU). • A monitor uses a Cathode Ray Tube (CRT) to display information. • CRT is a picture tube of computer. • CRT contains electron gun, the electron beam (controlled by an electromagnetic field), and a display screen. • The screen is coated with phosphor in a grid of dots called pixels. • The electron gun emits an electron beam, which is directed towards the phosphor-coated display by the electromagnetic field, and this in turn creates the image. Resolution: Images are formed on a monitor by a series of dots or pixels (picture elements). Resolution is expressed as a matrix of these dots or pixels. For eg, many monitors have 1,280 pixels columns by 1,024 pixel rows for total of 1,310,720 pixels. The quality of monitor depends upon the number of pixels (monitor’s resolution).
- 15. LCD (Liquid Crystal Display) • It is introduced in watches and clocks in 1970s like light-emitting diode (LED) and CRT. • LCDs consume much less power than LED and CRT. . • LCD is an electro-optical amplitude modulator which is thin and flat display device made up of many numbers of color or monochrome pixels arrayed in front of a light source or reflector. • It is also used in battery-powered electronic devices because it uses very small amounts of electric power. • It is expensive than CRT. • It has limited viewing angle
- 16. Printers • Printers are the peripheral device which produces output on paper. • The speed of printer is measured in Character per Second (CPS), Lines per Second (LPS), Pages per Second (PPS), depending upon the type of the printer. • These printers can be classified into 1. Impact printer : DMP, Line Printer 2. non-impact printer : Laser, Inkjet, Thermal
- 17. Impact Vs Non-Impact Printers NON-IMPACT PRINTERS IMPACT PRINTERS 1. Produce better quality print than impact printers 2. Non-impact printers are quieter i.e. noiseless 3. The characters and images are printed without any direct physical contact with the paper 4. Non-impact printers are usually more expensive than impact printers. 5. Non-Impact Printers are faster than Impact Printers (because they have fewer moving parts). 6. Speed of Non-Impact printer is generally measured in Pages Per Minutes (PPM) 7. Examples : Laser Printer, Inkjet Printer, Thermal Printer, etc 1. Produce worst quality print than non- impact printers 2. Non-impact printers generate noise (because of the hitting activity). 3. The characters and images are printed by making physical contact with paper. (in Dot matrix printer hammer is strike on paper along with carbon ribbon to print) 4. Impact printers are Cheaper than non-impact printers. 5. Impact Printers are slower than non- impact Printers. 6. Speed of Impact printer is generally measured in Character per seconds (CPS) or Line Per Minutes (LPM) 7. Examples : Dot Matrix Printer, Daisy Wheel Printer, etc
- 18. Dot Matrix Printers • DMP uses a print head consisting of a series of small pins to strike a ribbon coated with ink, causing the ink to transfer to the paper at the point of impact. • Characters produced are in a matrix format (set of dots) dotted form. • The shape of each character, i.e. the dot pattern, is depends upon number of pins present on head. • DMP can have 7 / 9 / 18 or 24 pins on print head. • Dot matrix printers can either be character-based or line-based. • It is cheapest, robust printer and low quality printer. • Its printing speed is 30–1000 cps (characters-per- second).
- 19. Laser Printers • Laser printer uses dry ink (toner), static electricity, & heat to place and bond the ink onto the paper. • They use a combination of laser and photocopier technology. • Produce image using laser beam on the photosensitive surface of a drum. The paper rolls by the drum, the toner is transferred to the paper and fixed into a permanent image. • To make the printing permanent; the heat and pressure is applied on the paper by passing it through a hot roller. • Laser printers are capable of converting computer output into print, page by page. • Laser is high quality, high speed, high volume printer that work on plain paper or pre-printer stationary. It is faster, noiseless, expensive but cost effective printer. • Speed ranges from 10 pages per minute to about 200ppm
- 20. Inkjet Printers • Inkjet printer uses a series of nozzles to spray drops of ink directly on the paper. • The print head consists of a number of tiny nozzles to spray ink on paper by making electrical field on paper. • Inkjet printers are slower than dot-matrix printers (40-300 cps), cheaper to buy but are more expensive in running costs (printing cost is higher). • Typical inkjet printers produce 17 to 19 pages per minute of b/w output and 13 to 15 pages of color output.
- 21. Thermal Printers • A thermal printer produces a printed image by selectively heating coated thermochromic paper, or thermal paper (heat sensitive paper) , when the paper passes over the thermal print head. • The coating turns black in the areas where it is heated, producing an image. • Thermal printer can also print in two different colour i.e. in black and an additional color (often red), by applying heat at two different temperatures. • Thermal printers print faster and more quietly than dot matrix printers. • It can produce high quality output in B/W or in colour. • It is economical printing solution as it require only paper (no need of ribbon or ink or toner, etc). Thermal printers are used in ATM, Kiosk, Shopping Malls, Petrol Pump, Hotels, etc.
- 22. Plottors • Plotters are used to produce graphical output on paper. • It can print charts, drawings, graphics, maps etc. • It is much similar to printer but it is designed to print graphs instead of alphanumeric characters. • Plotters are available in any size to generate bigger output. • Plotters are of two types: pen plotter and electrostatic plotter. Pen plotters have an ink pen attached to draw the images, electrostatic plotters work similar to a laser printer.
- 23. Voice Response Systems • Voice response systems enable the computer to talk to its users. • It consists of an audio-response device that produces the audio output. • To facilitate voice response computer must have a sound card attached/inbuilt into the computer system. Sound cards having digital-to-analog converter, that converts recorded or generated digital data into an analog format. • Audio-output devices • Voice Reproduction System • Speech Synthesizer
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