Keyboard
It
is the most common input device used for entering data and information into the
computer system. The keyboard is a primary device for inputting text by
pressing a set of keys. All the keys are neatly mounted in a keyboard connected
to the computer system. Keyboard devices can be classified into two types general
purpose keyboards and special purpose keyboards.
The
layout of keyboard is just like the traditional typewriter of the type QWERTY.
It also contains some extra command keys and function keys. It contains a
total of 101 (Minimum keys in standard Keyboard) to 104 keys. You have to
press a correct combination of keys to input data. The computer can recognize
the electrical signals corresponding to the correct key combination and
processing is done accordingly.
The
User can enter data into the computer by pressing a set of keys on the
keyboard. In a keyboard letters are printed on the keys. The first keyboard was
developed in the 18th century and was named as a QWERTY keyboard. A Computer
keyboard includes control circuitry which converts the key pressed by the user
into key codes so that the computer can understand it. Now-a-days wireless
keyboards are also being used which increase user freedom. The wireless feature
is achieved by infrared signals or by radio frequency.
In general, a computer keyboard has following keys:
1.
Alphanumeric keys: These are the keys which consists
of alphabets (a,b,c.......y,z), special symbols (!,@,>….&,*)
and numbers (1,2.....0).
2.
Punctuation keys: These are the keys which lies in
the numeric keys and displays the punctuation symbols when pressed
simultaneously with the shift key.
3.
Lock keys: Lock keys lock a part of a keyboard
depending on the lock setting selected. There are three lock in a keyboard and
they are number lock, scrolling lock and capital lock.
4.
Direction or Navigation keys: Direction keys
are the arrow keys which helps in moving left, right, up and down.
5.
Special Keys: Special keys are used to done some
special work like Insert, Delete, Home, End etc in shorter time of period.
6.
Function keys: Function keys are the soft keys which may
have default actions accessible on power-on. these keys lie on the top row of
the keyboard. The keys are (F1, F2,.......F12).
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