Parts of Computer (input device)

 There are two types of computer system 

1. The input device
2. The output device 

THE INPUT DEVICE 

Input refers to the data or instructions which we feed into a computer. Input devices are used to enter data and information into a computer. The Input unit converts the incoming data and instructions into a pattern of binary codes which is understood by a computer. Then it further supplies the converted data to the processor for processing. 

Some of the input devices are discussed below: 

KEYBOARD 

Keyboard is one of the most important input devices used to input data and instructions into a computer. There are mainly five types of keys on a keyboard: 

MOUSE

Mouse is the most commonly used input and pointing device that lets you select and move items on the screen. The left mouse button is used more frequently than the right button. A single left-click selects an item while double-clicking on an item activates the application.The right-click often displays a list of commands on the screen. You can also gain access to'Property'settings, with the right-click. Dragging and dropping makes it easy to mov.e an item on the screen. With this simple technique, one can delete, copy, and move files in a file manager. Mouse is also used in drawing packages to draw free-hand lines, circles, boxes, and other complicated graphic images.

STYLUS 

A stylus (or stylus pen) is a small instrument shaped like a pen that is used to provide input to mobile devices, computer screens, and tablets. It can be used to draw or make selections on touchscreen devices directly on the screen. Using stylus instead of a mouse or a trackball is also called pen computing. Stylus is used on game consoles like Nintendo. 

SCANNER

It is an input device that scans text, images, and objects optically. The scanned data is then converted into a digital image and displayed on the computer screen.

OCR (OPTICAL CHARACTER READER/RECOGNITION) 

It is used to read characters from a printed paper into the computer. The shape of the character is recognised by OCR through a light source in conjunction with photoelectric cells. When a text page is scanned, it is converted into a computer readable form and reproduced in a form that looks similar to a page that has been typed. The software then places the text into a document that can be edited using any word processor or text editor.

QMR (OPTICAL MARK READER/RECOGNITION) 

QMR is a device for capturing data_formed byjark and light marks on the Specificpositions ofthepaperjtls a special device that can detectmarks made with ink or pencil. OMR requires a special printed paper that contains boxes or circles for shading. The shaded marks are tcanslated into electrical signals ba^d on the presence QI[ absence of| shaded marks. This format is used by various entrance examinations for marking objective] type questions. The answer sheets are inserted into OMR for calculating the scores. It has' great speed and the marking is error free. 

MICR (MAGNETIC INK CHARACTER READER/ RECOGNITION) 

MICR is primarily used by the banking industry to facilitate the processing of cheques. This technology allows^omputers to read information (such as account the printed^ocuments. MICRch^acter^i^ptlntejyn special typefaces with a magnetic inkor tonerTusually'containihg jr^ox^ As a machine decodes the MICR text' j^first magnetises the characters-ln~the plane surface of the paper. Then, the characters^re passed over an MICR read head, a^device similar to the playback head of a tape recorder. As each character passes over ftTeTiead, it produces a unique wave form that can easily be identified by the system. Unlike barcodes or similar technologies, MICR codes can easily be read by humans. 

BAR CODE READER 

It is an input device used for reading bar codes printed on the packing of various products. A bar code is a combination of dark and light stripes. It is a computer readable representation of information, present in visual format. A bar code reader consists of a light source, a tens, and a light sensor for translating the optical impulses into electrical signals. Itisa very^iseful device for billing and inventory applications. 

JOYSTICKICK 

A joystick is an input device which allows the user to move an object on the screen. It is normally used in Gaming Centres for playing games. It has a moving stick (which rests on a base) with some push buttons on it. In fact, the stick movements are similar to the gear of a The physical movements of the stick are sent to the computer as inc the object at different positions on the screen. This creates simulations in the gamp making itexciting for the user. 

MICROPHONE

It is an input device used to record and store voice or any other sound into a computer, generally asa .wav file. It isalso used for recording a narration in a Powerpoint presentation. Generally, it is used as a separate. component for desktops but can be seen as an integrated component in some laptops, You can notice a special port in these computers where a microphone can be connected, Microphone is commonly used in video conferencing, speech recognition programs, radio broadcasting, recording, and sound amplifying systems. 

LIGHT PEN 

It is a light-sensitive pointing device, commonly used to select or modify data on the screen. It allows the user to point on displayed objects or draw on the screen. Its operation is similar to a touch screen but has greater positional accuracy. It is easy to use and helpful for programs like Computer Aided Design (CAD). 

VOICE INPUT DEVICES - SPEECH SOFTWARE 

A voice input device allows the user to control the computer through voice commands instead of using a keyboard. When the user speaks out a command, his/her voice gets recorded. Then the computer compares the pattern of the recorded voice to a series of patterns that are stored in the computer. This collection of patterns is called a vocabulary. Some specific action corresponding to a particular matching pattern is then executed. 

 DIGITAL CAMERA 

A digital camera is quite similar to a traditional camera that takes both video and still photographs except for the fact that digital images can be used, viewed and edited on a personal computer. We can also print the photos through a printer. It does not require a film roll like a normal camera.Nowadays, mobile phones have inbuilt digital cameras. A webcam is also a kind of digital camera connected to a computer. It is used for video conferencing and online charting.