keyboard

keyboard

keyboard:

Programs and data are entered into a computer through a key-board which is attached to a computer. A keyboard is similar to the keyboard of a typewriter. It contains alphabets, digits, special characters, function keys and some control keys. When a key is pressed, an electronic signal is produced which is detected by an electronic circuit called keyboard encoder . A computer includes all the keys found on a typewriter plus some additional keys. These additional keys are cursor control (i.e. moving the cursor around on the screen), insert, delete, and scroll control keys. There are a total of 101 keys (some have more). At the right side of the keyboard is the numeric keypad with numbers and basic mathematical symbols. 

keyboard daigram

    Numeric keypad can also be used for cursor control. This double function of numeric keypad is controlled by ( Num Lock ) key. 

The keyboard contains a small built-in processor. When you pre a key, the keyboard processor detects it and sends a number (binary nurnber) corresponding to that key (scan code) to the key-board cotitlIcr, located on the motherboard. This code is then finally transmitted to the processor (CPU). The CPU then processes it using a program called keyboard driver. The keyboard driver translates the codes into their corresponding characters. Different types of keys ind their functions are described in the following Sections.

    Standard Typewriter kays:

PC keyboard has a set of keys that closely resemble the keys found on a typewriter. These include the numeric keys (0 to 9), character keys (A to Z), special characters (!, @, #, $, etc.). These keys are often called QWERTY keys (named after the top row of letters).

    Function Keys:

Keys labelled as F1 to F12 carry out special functions in the soft-ware running in the PC. For example, the F1 key in most pro-grams displays the help file available for using that program.

   Cursor Movernenf Keys:

These ←, →, ↑, ↓arrow keys are used to move a cursor (a blinking line on the tivelyonitor) to the left, right, up or down respectively. In addition, there are four more keys, PGUP, PGDOWN, HOME, and END. This keys let you move the cursor quick throught text. The HOME and END keys are specially used for positioning the cursor at the 101 keys model of the keyboard, there is a separate set of cursor movement keys, namely ←, →, ↑, ↓ arrow keys. But in the case of old type 83 keys model of the key-board, you\need to press ( Num lock) key to change over between the numeric and cursor movement functions of the keys.