INPUT DEVICE

 

 INPUT DEVICE

A device through we give the input to computer are called input device. The process of entering data and instructions into the computer are called inputting and through this device is entering data and instructions are called input device.

We are using the following input devices. 

          * Keyboard

          * Mouse

          * Joystick

          * Light Pen

          * Touch Screen

          * Scanner

          * Optical Mark Reader

          * Smart Card

KEYBOARD

Keyboard is an input device. Keyboard is used for feeding the data into the CPU. Keyboard come in variety of sizes and shapes, But most keyboards used with computer system have a certain number of features in common:

(1)  Standard Typewriter Keys

(2)  Function Keys

(3)  Numeric Keys

(4)  Cursor Movement Keys

(5)  Indicator Keys & Special-Purpose Keys

(1)  Standard Typewriter Keys

This area is used to tyype  any text, it have a set of following keys-

(|)  A to Z alphabets key

(||)  0 to 9 numbers ke

(|||)  All symbols as   ,.<>/?";:[]#$%^&*() etc.

                                                         Figure 3.1- Keyboard

(2)  Function Keys

Each keyboard has twelve function keys (F1 to F12). Function keys also called programmable keys. Function keys are used to issue command. There are different works in different programs of the function keys.

(3)  Numeric Keys

Numeric keys are placed at the right side of a keyboard. This area has 0 to 9 numbers and cursor movement keys. If num lock is on then this area will do the work of numeric keys or if this area is locked then it will do the work of cursor movement keys.

(4)  Cursor Movement Keys

You can move the cursor on the screen by using cursor movement keys. This area has 4 arrow keys, home, end, insert, delete, pgup, pgdn etc keys.

(5)  Indicator keys & Special-Purpose Keys

Indicator Keys area has three keys (Caps Lock, Num Lock, and Scroll Lock). You can lock the area of the keyboard by these keys. Special-purpose keys have Ctrl, Alt, Shift keys.

MOUSE

The mouse is a hand-held device connected to the computer by a small cable. As the mouse is roll across the desktop, curser moves across the screen. when the curser reach the desired location, the user usually puss a button on the mouse once or twice two signal a 

                                                                 Figure 3.2- Mouse

menu selection or a command  to the computer. With special software for graphics, the mouse can be use like a pen or a paint to create figures and patterns directly on the video display screen.

JOYSTICK

Joystick is an input device used to play video games. A joystick uses a lever to control the position of the cursor. Joystick mostly used in play the games. It controls the cursor movement.

                                                              Figure 3.3- Joystick

LIGHT PEN

The light pen uses a light-sensitive photo electronic cell to signal screen position to the computer. The pen is pushed to close the photo electric circuit, there by indicating the x-y screen coordinates to the computer.

Figure 3.4- Light Pen

       Light pen is frequently used by graphics designers; illustrators and drafting engineers.

TOUCH SCREEN

Limited amount of data can be entered via a terminal or a micro computer that has a touch screen. The user simply touches the screen at the desired locations, marked by labeled boxes, to "point out " choices to the computer. A touch Screen registers input when finger or other object comes connects with the screen and these beams or waves.

SCANNER

Scanner is an input device that reads text & graphics from paper and enters it directly into the computer.

Figure 3.5- Scanner

OPTICAL MARK READER

The optical mark technology is used widely for scoring examinations questionnaires. For OMR to read the data accurately the forms must be carefully designed and manufactured and the marks must be recorded carefully, which is why the College Board is so insistent on your using a no. 2 pencil. OMR devices are easily available that will work both Apple and IBM compatible personal computer.

TRACK BALL

In a Track Ball, the roller ball is mounted in a fixed position and the user spins the ball in different directions to control the cursor movements on the screen.

                                                              Figure 3.6- Track Ball

SMART CARDS

Smart cards were pioneered in the mid-1970 in France, are designed to be carried like credit card but used like tiny transaction computers. To use, it the cardholder inserts the card into a special card reading point-of-sale terminal and then enters a password on the keyboard. which are updated each time the card is used. It France and Britain smart cards are used to pay cash.

                                                          Figure 3.7- Smart Card Reader