Computer Peripherals.Pdf
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ComputerComputer PeripheralsPeripherals Members: Julienne Mae Cacho Kim Catulong Mark Kevin Caccam Joy Enfesta WhatWhat isis ComputerComputer Peripheral?Peripheral? A computer peripheral, or peripheral device, is an external object that provides input and output for the computer. Some common devices •Monitorinclude: •keyboard •mouse •joystick •pen tablet •Speakers •scanner •Printer •modem •Video Card • ØComputerComputer MonitorMonitor The monitor is the device on which images produced by the computer operator or generated by the program are displayed on a cathode- ray tube (CRT ). Electron guns— one in a monochrome monitor, three in a color monitor— irradiate phosphors on the inside of the vacuum tube, causing them to glow. The flat- panel displays on most portable computers, known as liquid- crystal displays ( LCDs ), use two polarizing filters with liquid crystals between them to produce the image. See also Electronic display; Liquid crystals. ØComputerComputer KeyboardKeyboard The computer keyboard, based on the typewriter keyboard, contains keys for entering letters, numbers, and punctuation marks, as well as keys to change the meaning of other keys. The function keys perform tasks that vary from program to program. ØComputerComputer MouseMouse The mouse is a device that is rolled on the desktop to move the cursor on the screen. A ball on the bottom of the mouse translates the device's movements to sensors within the mouse and then through the connecting port to the computer. There are also mice that substitute optical devices for mechanical balls, and mice that use infrared rather than physical connections. The trackball is essentially an upside- down mouse, with the ball that is used to move the cursor located on the top rather than on the bottom. ØComputerComputer JoyJoy StickStick A peripheral input device that looks similar to a control device you would find on an arcade game at your local arcades. A computer joystick allows an individual to easily navigate an object in a game such as navigating a plane in a flight simulator. ØComputerComputer ScannerScanner The scanner converts an image of something outside the computer, such as text, a drawing, or a photograph, into a digital image that it sends into the computer for display or further processing. The image is viewed as a graphics image, not a text image, so it can be altered with a graphics program but cannot be edited with a word- processing program, unless the scanner is part of a character- recognition system. To digitize photographs, a scanner may dither the image ( put the dots a varying amount of space apart), or use the tagged image file format (TIFF ), storing the image in 16 gray values. Some scanners can use standard video cameras to capture images for the computer. ØComputerComputer PrinterPrinter Aprinter is a peripheral which produces a hard copy (permanent 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 peripherals, Individual printers are often and are attached by a designed to support both local printer cable or, in most and network connected users at newer printers, a USB cable the same time. In addition, a few to a computer which serves modern printers can directly as a document source. Some interface to electronic media printers, commonly known as such as memory sticks or memory network printers, have cards, or to image capture built- in network interfaces devices such as digital cameras, (typically wireless and/ or scanners; some printers are Ethernet), and can serve as combined with a scanners and/ or a hardcopy device for any fax machines in a single unit, user on the network. and can function as photocopiers. ØComputerComputer ModemModem A modem ( modulator - demodulator ) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog signals, from driven diodes to radio. The most familiar example is a voiceband modem that turns the digital 1s and 0s of a personal computer into sounds that can be transmitted over the telephone lines of plain old telephone services (POTS ), and once received on the other side, converts those 1s and 0s back into a form used by a USB, Ethernet, serial, or network connection. ØVideoVideo CardCard A video card, video adapter, graphics- accelerator card, display adapter or graphics card is an expansion card whose function is to generate and output images to a display. Many video cards offer added functions, such as accelerated rendering of 3D scenes and 2D graphics, video capture, TV- tuner adapter, MPEG- 2 / MPEG - 4 decoding, FireWire, light pen, TV output, or the ability to connect multiple monitors (multi - monitor ). Other modern high performance video cards are used for more graphically demanding purposes, such as PC games. ØComputerComputer SpeakersSpeakers Computer speakers, or multimedia speakers, are speakers external to a computer, that disable the lower fidelity built- in speaker. They often have a low- power internal amplifier. The standard audio connection is a 3. 5mm ( 1 / 8 inch) stereo jack plug often colour- coded lime green ( following the PC 99 standard) for computer sound cards. A plug and socket for a two- wire ( signal and ground) coaxial cable that is widely used to connect analog audio and video components. Also called a " phono connector," rows of RCA sockets are found on the backs of stereo amplifier and numerous A/ V products. The prong is 1/" 8 thick by 5/" 16 long. 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 half a watt of output power. ØComputerComputer CameraCamera A video camera is a camera used for electronic motion picture acquisition, initially developed by the television industry but now common in other applications as well. The earliest video cameras were those of John Logie Baird, based on the electromechanical Nipkow disk and used by the BBC in experimental broadcasts through the 1930s. All- electronic designs based on the cathode ray tube, such as Vladimir Zworykin's Iconoscope and Philo T. Farnsworth's Image dissector, supplanted the Baird system by the 1940s and remained in wide use until the 1980s, when cameras based on solid- state image sensors such as CCDs ( and later CMOS active pixel sensors) eliminated common problems with tube technologies such as burn- in and made digital video workflow practical. ØComputerComputer MicrophoneMicrophone Generally Microphones are a separate computer component, some manufacturers are integrating the microphone into computers. Generally, integrated microphones can be found on laptops and some desktop monitors. Integrated Microphones are usually a small hole in front of the computer which when spoken into will record your voice. When connecting the microphone to the back of the computer, the microphone will be placed in the hole which generally has Mic or Microphone written next to it as illustrated in the above illustration. ØComputerComputer ProjectorProjector An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern analog of the slide projector or overhead projector. To display images, LCD ( liquid crystal display) projectors typically send light from a Metal As polarized light passes through the halide lamp through panels ( combination of polarizer, LCD panel a prism that and analyzer), individual pixels can be separates light to opened to allow light to pass or closed to three poly silicone block the light. The combination of open and panels – one each closed pixels can produce a wide range of for the red, green, colors and shades in the projected image. and blue components of the video signal. EndEnd ofof presentationpresentation •⤌.