3. What is Input "Any data or instruction that is entered into a computer is called input". This data or instruction can come directly from end user or from other devices.

4. What is input device? "An input device is a hardware device that is used to take data / instructions from the outside world into the computer so that it can be processed".

5. For example, while you prepare word documents or spread sheets, you use the keyboard to enter text & numbers and use command keys to save / print documents.

6. You can also perform operations on computer using voice commands. These are all different methods of providing an input to a computer.

7. Besides the widely used input devices like keyboard & Mic there are other different input devices that perform various input operations like a scanner scan images / documents. Webcams capture videos & images

8. Keyboard The keyboard is the primary text input device of your computer it combines a typewriter keyboard with a numeric keypad.

9. Mouse The mouse is another essential input device that controls the pointer displayed on the monitor. A mouse can have 2 or more buttons. Mostly the Right-Mouse Button and the Left-Mouse button, and a wheel button for scrolling pages.

10. There are two types of mouse

11. Optical mouse Optical Mouse is widely used these days. Like the mechanical mouse, it does not have any moving parts. It emits & senses light to detect mouse movements. Optical mouse can be used on any surface with great precision as compared to Mechanical mouse.

12. Mechanical Mouse A mechanical mouse is considered as the traditional mouse and is now replaced by optical mouse. A mechanical mouse has a ball on the bottom, which is attached to the system unit through a cord. A mechanical mouse requires periodic cleaning.

14. Joystick A very popular input device that is used for computer games. Different buttons are used for controlling the game. They can be used with gaming consoles like Xbox 360 or Playstation.

15. Touch Screen A touch screen is a particular kind of monitor screen covered with a plastic layer. Behind this layer are crisscrossed invisible beams of infrared light. This arrangement enables someone to perform actions by touching the screen with a finger or stylus.

16. With it growing popularity touchscreens are used in smartphones, Automated Teller Machine (ATM) etc.

17. Optical Scanner A scanner reads data or information from a source. This source can be a written document, on an image. A scanner, also called optical scanner can copy or reproduce text as well as images.

18. Bar Code Reader A barcode reader is a photoelectric scanner that reads the bar codes of a product. The bar code reader reads the bar code of a product and displays the information about the product.

19. Optical Mark Recognition (OMR) Optical mark recognition (OMR) is an electronic method of gathering human- handled data by identifying certain markings on a document.

20. Optical Character reader (OCR) – Senses the patterns of reflected light off scanned text through photo electric device and compares it to the pattern in memory.

21. Magnetic Ink Character Recognition (MICR) – is a device used to verify the legitimacy or originality of paper documents, especially checks. Special ink, which is sensitive to magnetic fields, is used in the printing of certain characters on the original documents. Information can be encoded in the magnetic characters.

22. Light Pen A light pen is a light-sensitive computer input device, basically a stylus, that is used to select text, draw pictures and interact with user interface elements on a computer screen or monitor.