Sunday 27 January 2013

Component of Computer





 

INPUT DEVICE

An input device is any device that provides input to a computer. There are dozens of possible input devices, but the two most common ones are a keyboard and mouse. Every key you press on the keyboard and every movement or click you make with the mouse sends a specific input signal to the computer. These commands allow you to open programs, type messages, drag objects, and perform many other functions on your computer.
Since the job of a computer is primarily to process input, computers are pretty useless without input devices.  Just imagine how much fun you would have using your computer without a keyboard or mouse. Not very much. Therefore, input devices are a vital part of every computer system.
While most computers come with a keyboard and mouse, other input devices may also be used to send information to the computer. Some examples include joysticks, MIDI keyboards, microphones, scanners, digital cameras, webcams, card readers, UPC scanners, and scientific measuring equipment. All these devices send information to the computer and therefore are categorized as input devices. Peripherals that output data from the computer are called output devices.
The input unit is formed by the input devices attached to the computer. Ex - Keyboard, Microphone etc. An input unit takes the input & converts it into binary form so that it can be understood by the computer.



KEYBOARD
This is most commonly used device which acts as input device. Its structure is like typewriter.It contains no. of  keys which have some specific ASCII values. Like ‘A’ has ASCII value 65. When this is pressed , it is converted into 65 & this 65 is sent to CPU in the form of Binary language (i.e. 1000001). Then operations are done on this data.


MOUSE
This is a pointing device which contains a roller in its base. When the mouse is moved on any surface, the pointer on the screen is also moved. It contains a potentiometer coupled with the roller. This potentiometer senses the motion of mouse & convert it into digital value. A mouse may contain two or three buttons.
Now a day's optical mouse are very popular.


BAR CODE READER
It is a device which is used to read the code from the products which are usually in the form of Bars. It contains a light sensitive detector which identifies the values of the bars on the product & converts them into numeric code.
These Bar readers are used in Shopping malls in a very large scale.



DIGITAL CAMERA
As the name specifies, these camera stores the data digitally, which then can be stored in the computer & can be stored for a long time. But it has very limited storage capacity. These are very popular because of less expensive photographs & Speed.



LIGHT PEN
It is a pointing device which contains a photocell mounted at its tip. It senses the light from the screen when it  becomes closer to the screen, & generates a pulse. So for identifying a particular location on the screen these light pens are very useful. But this is not in very much use these days.



SCANNER
The scanner is an input device like the photocopier machine which makes the electronic copy of the picture or document which can be further edited. 




 MIC's or MICROPHONES
The scanner is an input device like the photocopier machine which makes the electronic copy of the picture or document which can be furth.
 

                                                   
CAMERA
Most cameras like this are used during live conversations.  The camera transmits a picture from one computer to another, or can be used to record a short video.





COMPACT DISC (CD)
CDs store information.  The CD can then be put into another computer, and the information can be opened and added or used on the second computer.
Note:  A CD-R or CD-RW can also be used as an OUTPUT device.




JOYSTICK
A joystick is used to move the cursor from place to place, and to click on various items in programs.  A joystick is used mostly for computer games.




TOUCH SCREEN
A touch screen is a computer screen or other screen that you can touch with your finger to enter information.  Examples of touch screens include a smart board, a microwave, a dishwasher, or an ATM at a bank.