1. Keyboard
Keyboard is the most commonly used input device today. They allow data and text entry into a computer system by pressing a set of keys. The most popular keyboard used today is QWERTY with 101 keys. It is made up of button called keys. The keys are arranged in section.
A standard keyboard consists of the following keys:
Alphanumeric keys: It includes numeric keys and alphabet keys.
Function keys: It is arranged in a row on the top of the keyboard. It performs task such as searching files and refreshing web pages.
Control keys: It controls the movement of cursor. Example Shift, Alt and Ctrl.
Numeric keypad: It is located on the right side of the keyboard.
Special key: Insert, Delete, Print screen, Tab, Space bar, Escape, etc.
2. Mouse
A mouse is a small hand held device that makes two-dimensional movement of the cursor on the display screen. It is an input part of GUI based operating system as it helps in selecting a portion of the screen and copying and pasting the text.
Mechanical Mouse
It consists of three buttons: left, right and semi button, inside there is a ball which is rolled over a flat surface. Left button is the most frequently used button; it helps in selecting the icon, folder, text on the display screen. Right button helps to display shortcut menu. Scroll button help in moving the cursor up and down on the screen by scrolling.
Optical Mouse
It has no mechanical part like ball and wheel, instead it has a reflected light which determine the movement of the cursor on the display screen.
3. Track ball
It is a point device that basically consists of a socket containing a ball, which can be rolled manually to move the cursor on the screen. The socket contains the sensors, which detect the movement of the ball. Two types of track ball are small track ball and large track ball. Small track ball are commonly used in portable computer. Large track ball are used for desktop computer used for CAD. It is use in fame controller in game like centipede, Golden Tee and Marble madness.
4. Joystick
A Joystick is a pointing device that consists of one or more buttons and sticks, which controls the movement of the cursor on the screen by pointing in all directions. Most joysticks include two buttons called triggers. To make the movement of the ball, it is placed in a socket with a stick mounted on it. A user holds the stick in his/her hand and moves it around to move the spherical ball. The user can move the stick forward or backward, left or right; the user clicks the button to make the selection. The joystick is generally used in computer games, CAD system, industrial application, etc.
5. Light pen
Light pen is an Electra optical pointing device that is used for selecting the object on the display screen or draw pictures with the help of light sensitive pen. It is generally connected to the Visual Display Unit of the computer system. It contains light sensitive diode, which helps in pointing the object displayed on the screen and select object directly pointing to the objects with the pen. We can directly draw the objects on the screen by holding it in our hand.
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