INPUT DEVICES

Following are few of the important input devices which are used in a computer:

  • Keyboard
  • Mouse
  • Joystick
  • Light Pen
  • Track Ball
  • Scanner
  • Graphic Tablet
  • Microphone
  • Bar Code Reader
  • Magnetic Ink Card Reader(MICR)
  • Optical Character Reader(OCR)
  • Optical Mark Reader(OMR)

Keyboard:

Keyboard is the most common and very popular input device which helps to input the data to the computer.

Computer keyboards are similar to electric-typewriter keyboards but contain additional keys.

The keyboard layout is known as the QWERTY design, which gets its name from the first six letters across in the upper-left-hand corner of the keyboard.

Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and Internet.

The keys typically found on computer keyboards are often classified as follows:

  • Typing Keys
  • Numeric Keys
  • Function Keys
  • Control Keys
  • Special Purpose Keys

Typing Keys:

These keys include the letter keys (A-Z) and digit keys (0-9) which generally give same layout as that of typewriters.

Numeric Keys:

It is used to enter numeric data or cursor movement. Generally, it consists of a set of 17 keys

Function Keys:

The Twelve function keys are present on the keyboard which is arranged in a row at the top of the keyboard.

Each function key has unique meaning and is used for some specific purpose. for e.g. F1, F2 etc.

Control Keys:

These keys provide cursor and screen control. It includes four directional arrow keys.

Control keys also include Home, End, Insert, Delete, Page Up, Page Down, Control(Ctrl), Alternate(Alt), Escape(Esc).

Special Purpose Keys:

Keyboard also contains some special purpose keys such as Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, and Print Screen.

 


Mouse:

A device that controls the movement of the cursor or pointer on a display screen is called Mouse

A mouse is a small object you can roll along a hard, flat surface.

Its name is derived from its shape which looks a bit like a mouse.

Generally it has two buttons called left and right button and a wheel is present between the buttons.

It moves the cursor faster than the arrow keys of keyboard.

 


Joystick:

Joystick is also a pointing device which is used to move cursor position on a monitor screen.

It is a stick having a spherical ball at its both lower and upper ends.

The Joystick can be moved in all four directions.

Ihe Joystick is similar to a mouse

It is mainly used in Computer Aided Designing (CAD) and playing computer games.

 


Light Pen:

Light Pen is a light-sensitive pointing device commonly used to select or otherwise modify text or data on a screen.

The term Light Pen may also refer to a pointing device that is commonly used during a presentation.

It is similar to a mouse, except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen.

 


Track Ball:

Trackball is a computer cursor control device used in many notebook and laptop computers.

It is an input device that looks like an upside-down mouse. The onscreen pointer is moved by the trackball with a thumb or finger.

A trackball requires less arm and wrist motion that a regular mouse takes and therefore is often less stressful for the user to use.

 


Scanner:

Scanner is an input device which works more like a photocopy machine.

Scanners allow a user to take a printed picture or document and convert it into a digital file. It allows a computer to read or display the file.

A Scanner can be connected to a computer using USB, Fire wire or Parallel port

There are hand-held, flat-bed or feed-in types of scanner available.

 


Digitizer:

Digitizer is an input device which converts analog information into digital form.

Digitizer is also known as Tablet or Graphics Tablet because it converts graphics and pictorial data into binary inputs.

These tablets may also be used to capture data or handwritten signatures.

It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the tablet surface.

 


Microphone:

Microphone is a device that captures audio by converting sound waves into an electrical signal.

This signal can be amplified as an analog signal or may be converted to a digital signal, which can be processed by a computer or other device.

Below is a short list of all the different uses a microphone could be used for on a computer.

  • Voice Recognition
  • Computer Gaming
  • Online Chatting
  • Recording musical instruments

 


Bar Code Reader:

Barcode Reader is a hand-held or stationary input device used to capture and read information contained in a bar code

A Barcode Reader consists of a scanner, a decoder and a cable used to connect the reader with a computer.

Barcodes are often used to help organize and index information or prices about an object.

 


MICR:

Magnetic ink character recognition (MICR) is a character recognition system that uses special ink and characters.

MICR technology is generally used in banks because of a large number of cheques to be processed every day.

The information that appears at the bottom of a check that includes the bank’s routing number, the customer’s account number, and the check number.

The magnetic ink character recognition line is printed using technology that allows computers to read the printed information.

Using MICR, computers can quickly read routing numbers, account numbers and other information from printed documents including checks.

The main advantage of MICR is that it is fast and less error prone.

 


OCR:

Optical Character Reader (OCR) is an input device used to read a printed text.

OCR scans text optically character by character, converts them into a machine readable code and stores the text on the system memory.

 


OMR:

Optical Marker Reader (OMR) is the process of capturing human-marked data from document forms such as surveys and tests.

OMR allows for the processing of hundreds or thousands of physical documents per hour.

For example, students may recall taking tests where they filled in bubbles on paper with pencil or black pen.

Once the form had been completed, a teacher would feed the cards into a system that grades or gathers information from them.

 

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