Input and Output

Devices

By- Aman Barma.

Input and output devices are interfaces between the real world of objects and the computer world of symbolic representa-tion of information.

Input DevicesThe input unit is respo-nsible for accepting input i.e. DATA INSTRUCTION’S from the user .

KeyboardKeyboard is a typewriter like a device which is used to type letters, digits and commands.

keyboard

MouseThe Mouse is a pointing device with a roller on its base. When a Mouse moves on a flat surface , the cursor on the screen also moves in the direction of Mouse’s movement.

mouse

Microphone {mic}

A mic converts the sound received into computers format, which is called DIGITIZED SOUND or DIGITAL AUDIO.A MIC can work if our PC has a hardware known as SOUND CARD.

Mic

OUTPUT DEVICES

The output unit is responsible for producing the output in user redable form. Some of the output devices are Monitor, Printer, Plotter etc.Computer sends output through Monitor.

MONITORMonitor {or screen} is the most common form of output from a computer. The picture on a monitor is made up of thousands of of tiny coloured dots called pixels. The two most common Monitor are Cathode Ray Tube and Liduid Crystal Display .

Cathode ray tubeCRT contains an electron gun at the back of the glass tube. This fires electrons at groups of phosphor dots, which coat the inside of screen. When the electrons strike the phosphor dots they glow to give the colours.

Cathode Ray Tube

Liquid crystal display

LIQUID CRYSTAL is the material used to creat each pixel on the screen. The material has a special property –it can ‘polarise’ light depending on the electrical charge across it. This feature allows the pixels to be created. THIN FLIM TRANSISTOR is the device with in each pixel that sets the charge.

Liquid crystal display

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

Impact PrinterIn Impact Printers, there is contact between the printer head and paper.Impact printer comes in lots of varities such as Line Printer, Drum Printer, Daisy Wheel Printer and Dot Matrix Printer.

Dot-matrix Printer

A Dot-Matrix Printer is the most popular serial printer i.e. it print one character at a time. In, DMP, the printing head contains a vertical array of pins. As the head moves across the paper ,selected pins fire against an inked ribbon to form a pattern of dots on the paper. There are 80 column and 132 column DMPs available in the market.

Non-impact printerIn Non-Impact Printers, there is no mechanism contact between the printer head and paper.The natural limitation of speed in electromechanical devices and cost consideration have led to the development fo printers called Non-Impact Printer.

Types of n-ipi. Electromagnetic

Printers.ii. Thermal Printersiii.Electrostatic Printers.iv.Inkjet Printer.v. Laser Printer

printer

SpeakersSpeaker receives the sound from electric current from the sound card and then convert it to sound format.

speaker