Input and Output Devices

It is the most commonly used input device. It is used to enter data and instructions directly into the computer. There are 104 buttons on the keyboard which are called keys.

Mouse is another input device which is commonly found connected with the computers. It is basically a pointing device which works on the principle of Point and Click. When the mouse is moved on the mouse pad, a light beam underneath reflect to give motion to the pointer on the screen. The mouse is used in windows based programs, where the user can run the commands by pointing the objects with the help of pointer and clicking the buttons on the mouse. We also use mouse for drawing in paint and kid pix.

• Joystick and game-pad are also input devices which are also input devices which are used to control the movement of object on the screen. Just like mouse, these are also pointing devices. Mostly they are used for playing games on the computer. The joystick has a vertical stick with a track ball at its bottom. While playing the games on the computer, the user needs to move the objects quickly on the screen. With the movement of this vertical
• Light pen is another pointing type input device. It is a pen shaped device which can be used by directly pointing the objects on the screen. It can also be used for making drawings directly on the monitor screen.
• Scanner- We can store pictures, photographs, diagrams into the computer with the help of scanner. The scanner reads the image and saves it in the computer as a file
• Touchscreen is a special computer screen that takes the input by sensing the touch of a human finger, gloved hand, stylus, pen or any other pointing device. The user gives instructions to the computer just by touching the screen.
• Microphone- This is an input device which is used to record sound or voice into the computer system. You can store voice data in the computer by speaking in front of this device.
• A trackball is similar to a mouse but is mounted in a fixed position. The user spins the ball with fingers to move the pointer on the screen. A Trackball technology was used in earlier laptop computer which is now replaced with track-pad.

The devices which are used to display the results or information are called Output Devices. You can view the output on the monitor or you can print it on a paper using a printer. Monitor and the printer are the commonly used output devices.

This is the most common output device connected with the computer to display the processed information. It looks like a TV and is also know as VDU(Visual Display Unit). Pictures are displayed by using a large number of very small dots on screen called pixels. The number of pixels that a monitor can show on its screen is referred to as the resolution of the screen.

This is an important output device of the computer system. It gives a printed output of the results that appears on the monitor screen. Printed output is also called Hard Copy output because unlike monitor, this output can be preserved even if the computer is switched off.