Practical 2

2. List out input devices and output devices and explain in brief.

Input Device:

Entering data or instruction into the computer is called input. Therefore input device is a device which enters data or instructions into the computer.

Input device accept the data from the user and convert into the form accepted by computer.

Examples of input devices are: Keyboard, Mouse, Web Cam, Microphone, Scanner, Trackball, Joystick, Digitizer etc

Keyboard:

Keyboard is most common input device is used today. The data and instructions are input by typing on the keyboard. The message typed on the keyboard reaches the memory unit of a computer. It’s connected to a computer via a cable. Apart from alphabet and numeral keys, it has other function keys for performing different functions. Nowadays it has round about 104 keys.

  

Mouse:

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.

 

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. Thus the scanner converts any type of printed or written information including photographs into digital pulses, which can be manipulated by the computer. 

 

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. 

 

Touch Screen:

Touch screen 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.

 

Trackball:

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.

 

Output Device:

The information we get from the computer is known as output.

Processed data (result/information) return to the user through output device.

Output device convert the machine readable information into human readable form.

Example of output devices are: Monitor, Printer, Speaker, Plotter etc.

Monitor
This is the most common output device connected with the computer to display the processed information. It looks like a TV and is also known as VDU (Visual Display Unit). The number of pixels that a monitor can show on its screen is referred to as the resolution of the screen. Commonly used monitors are

CRT - Cathode Ray Tube

LCD – Liquid Crystal Display

 

Printer
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.

 

Speaker
Speaker is an output device. Speakers are used for listening music and audio played by the computer. Normally they come in a pair and have different shapes and sizes.

 

Plotter:

We can get the print of a photograph, drawing, image stored in the computer, by using a plotter. It is an output device which provides a high quality of printed output. It is generally used by engineers and architects.