INPUT AND OUTPUT DEVICES

 INPUT DEVICES: The devices through which we enter data and instructions are called Input devices. Examples:  Keyboard: It is used to input data and instructions into the computer. A standard keyboard has 104 keys which are divided into four groupsTyping keys, Function keys, Navigation keys and Control keys. Sir Christopher Latham Sholes was the inventor of QWERTY keyboard.

Joystick-It is a device used to control cursor on screen. Normally it is used in Games and specially designed simulation software.

Barcode reader:-

It is used to accept barcode inputs. A barcode is a series of vertical bars representing numbers and alphabets printed on product labels. One must have noticed all standard items like perfumes, greeting cards, books, cassettes available in the market have similar lines as shown in the figure, known as bar codes. These can be read with the help of bar code readers. 

Mouse: It is a hand-held pointing device. It is used to control the movement of the pointer to select an object, open files and folders and draw pictures etc. Dr Engelbart is the inventor of computer mouse.

Microphone: It is used to record voice, music and sound into the computer system.

Touchpad: On a laptop, a touch sensitive pad is used. We can control the movement of the pointer on the screen by moving the finger on the touchpad.

Touchscreen: It is a computer screen sensitive to the touch. On a touchscreen we can select objects directly by touching them with fingers. They are used in cell phones, laptops, ATMs etc. 

Light pen: It is a pen like pointing device used to select objects on the display screen. 

Digital Camera: It is used to take photographs and record videos which are stored in the memory chip inside the camera. 

Web Camera: It is connected to the computer for capturing still images and live videos. It can be used to chat live with friends and relatives using the internet.

Scanner: It is a device that reads the text or pictures printed on a paper and translates the information into a form that a computer understands. Two commonly used scanners are: 

1. Flatbed scanner

2. Handheld scanner

OUTPUT DEVICES

Printers Dot Matrix Printer The printers are classified as under: 

• Impact Printers - These printers have a mechanism that touches the paper in order to create an image. The Dot Matrix Printer is an example of this type

. • Non-impact Printers - These printers do not touch the paper when creating an image. The inkjet and laser printers are examples of this type.  

Plotters are expensive output devices specially designed to produce outputs of diagrams, illustrations and other graphics

A Monitor is an output device, very similar to the television screen. It displays the information as it is typed and also displays the processed result or the output. It is available in many forms cathode ray picture tube based display, liquid crystal based display(LCD), plasma panel display, and touch panel display


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