Hardware: Input / Output Devices COMPUTER Hardware: Input / Output Devices

Input Devices An input device is any hardware component that allows you to enter data and instructions onto a computer. Six Widely used input devices are the keyboard, mouse, microphone, scanner, digital camera and PC video camera.

Keyboards & Mice Keyboard is a typewriter like device which is used to type letters, digits and commands. A keyboard contains a matrix of switches (one switch per key). Each key, when pressed, send a digital code to the computer that determines which key has been pressed.

MOUSE mouse is pointing device that points to a position on computer screen. mouse controls movement of pointer (also called mouse pointer) on screen

Microphones A microphone converts the sound received into computer’s format, which is called digitized sound or digital audio.

Scanners A scanner creates an electronic form of the printed image, which can later be manipulated, changed and modified according to the requirement. Scanner comes in variety of sizes from hand-held model to desktop models. 1. Hand-held Scanners 2. Flatbed Scanners 3. Drum Scanners Hand-held Scanner

Flatbed Scanner Drum Scanner

Bar Code Reader The bar code uses lasers to identify the position and thickness of the bars.

Magnetic Stripe Reader Data is encoded magnetically on the strip and read by a machine as it is swiped.

OMR-Optical marks reader Read marks at designated positions.

Optical Character Reader OCR Optical Character Reader Scan a printed document and convert it into editable text.

Magnetic ink character reader MICR Magnetic ink character reader Read the magnetized ink characters.

Light Pen A light Sensitive input device shaped like a pen, used to draw on the computer screen or to make menu selections.

Output Devices The output unit is responsible for producing the output in user readable form. Various output devices like monitor(also called VDU i.e. Visual Display Unit. Three commonly used output devices are a printer, a monitor and speakers.

Monitors Monitor (or Screen) is the most common form of output from a computer. Types of Monitor 1. CRT 2. LCD (OR TFT) Plasma Monitor Touch screen monitor OLED monitor

CRT (CATHODE RAY TUBE) CRT contain an electron gun at the back of the glass tube. This fires electrons at groups of phosphor dots, which coat the inside of the screen. When the electrons strike the phosphor dots they glow to give the colours.

LCD – Liquid crystal Display or TFT- Thin film Transistor Liquid crystal is the material used to create each pixel on the screen. The material has a special property – it can ‘Polarise’ light depending on the electrical charge across it.

Plasma Monitors Plasma monitors or PDP (Plasma Display Panels) are flat panel displays. The Plasma technology utilizes small cells containing electrically charged ionized gases across the face of a plasma display, to collectively form of visual image.

OLED Monitor Organic Light Emitting Display OLED monitors are created from pushing an electronic current through organic materials, causing these material to glow.

Printers A most convenient and useful method by which the computer can deliver is by means of printed character. Printer can be divided into two distinct categories: 1. Impact printer 2 Non Impact Printer

Impact Printers In these printers, there is mechanical contact between the print head and paper. Most common impact printer is Dot Matrix Printer.

Non Impact Printers In these printers, there is no mechanical contact between the print head and paper. Advantage of non-impact printer are: High Speed, Cost effective, Better Print quality. Example: inkjet printer and laser printer.

Plotter The plotter is a graphic output device used to create drawings on paper. There are two types of plotters: Pen Plotter. It is an electromechanical device. A pen is moved in two dimensions (up/down and left right) across a paper or film media to create output. Photo Plotter. It uses fiber optics technology to produce the image on paper.

PEN PLOTTER PHOTO PLOTTER

Speakers Speaker receive the sound in form of electric current from the sound card and then convert it to sound format.

Slide Projectors A projector is an output device that can take the display of a computer screen and project a large version of it onto a flat surface.

Storage Media Secondary storage devices are used to store large amount of data permanently. Some most common storage devices are: Magnetic media Hard disks Floppy disks Optical media CD ROMs (Compact Disc) DVDs Flash memories Pen drive

Hard disks FLOPPY DRIVE FLASH DRIVE