Computer input device | input device | tech blog |

 

COMPUTER INPUT DEVICE

Keyboard

Keyboard is the most common and very popular input device which helps to input data to the computer. The layout of the keyboard is like that of a traditional typewriter although there are some additional keys provided for performing additional functions.

 

Keyboards are of two sizes 84 key or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for windows and the internet

S.NO.	Keys & description
1	Typing keys These keys include the letter keys (a-Z) and digit keys (09) which generally give the same layout as that of typewriters.
2	Numeric keyboard It is used to enter the numeric data or cursor movement. Generally, it consists of a set of  17 keys that are laid out in the same configuration used by most adding machines and calculators.
3	Function keys The twelve function key are present on the keyboard which is arranged in a row at the top of the keyboard. Each function key has a unique meaning and is used for some specific purpose.
4	Control keys These keys provide cursor and screen control. It included four directional arrow keys. Control keys also include home, end, insert, delete, page up, page down, control(ctrl) alternate(alt), escape(ESC)
5	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

The mouse is the most popular pointed device. It is a very famous cursor control device having a small palm-size box with a round ball at its base, which senses the movement of the mouse and sends corresponding signals to the CPU when the mouse buttons are pressed.

Generally, it has two buttons called the left and the right buttons and a wheel is present between the buttons. A mouse can be used to control the position of the cursor on the screen, but it cannot be used to enter text into the computer

 

·        Advantages

Easy to use

Not very expensive

Moves the cursor faster than the arrow keys of the keyboards.

 

Joystick

Joystick is also a pointed device, which is used to move the cursor position on a monitor screen. It is a stick having a spherical ball at both lower and upper ends. The lower spherical ball moves in a socket. The joystick can be moved in all four directions.

The function of the joystick is similar to that of a mouse. It is mainly used in computer-aided designing and playing computer games.

Light pen

The light pen is a pointing device similar to a pen. It is used to select a displayed menu item or draw pictures on the monitor screen. It consists of a photocell and an optical system placed in a small tube.

 

 

When the tip of a light pen is moved over the monitor screen and the pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signal to the CPU.

Trackball

The trackball is an input device that is mostly used in notebook or laptop computers, instead of a mouse. This is a half inserted ball, and by moving fingers on the ball, the pointer can be moved.

 

Since the whole device is not moved, a trackball requires less space than a mouse. A trackball comes in various shapes like a ball, a button, or a square.

Scanner

Scanner is an input device, which works more like a photocopy machine. It is used when some information is available on paper and it is to be transferred to the hard disk of the computer for further manipulation.

 

Scanner captures images from the source which are then converted into a digital form that can be stored on the disk. These images can be edited before they are printed.

MICROPHONE

A microphone is an input device to input a sound that is then stored in a digital form.

 

The microphone is used for various applications such as adding sound to a multimedia presentation or for mixing music.

Magnetic ink card reader (MICR)

A micro input device is generally used in banks as there is a large number of cheques to be processed every day. The bank’s code number and cheque number are printed on the cheques with a special type of ink that contains particles of magnetic material that are machine readable.

 

This reading process is called magnetic ink character recognition (MICR). The main advantage of micro is that it is fast and less error-prone.

Optical character reader (OCR )

 Ocr is an input device used to read a printed text.OCR scans the text optically character by character converts

 

 them into a machine-readable code. And stores the text on the system memory.

Bar code readers

A bar code reader is a device used for reading bar-coded data (data in the form of light and dark lines). Barcoded data is generally used in labeling goods, numbering the books, etc. it may be a handheld scanner or may be embedded in a stationary scanner.

 

 

Bar code reader scans a bar code image, converts it into an alphanumeric value, which is then fed to the computer that the bar code reader is connected to.

Optical mark reader (omr)

Omr is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked.

 

It is specially used for checking the answer sheets of examinations having multiple-choice questions.