Page 62 - AI Ver 1.0 Class 9
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Light Pen
                       A light pen is a pointing device shaped like a pen and is connected to a VDU. The tip of the light
                       pen contains a light-sensitive element which, when placed against the screen, detects the light
                       from the screen enabling the computer to identify the location of the pen on the screen. We
          Light Pen    generally use it to make a selection or draw anything on a screen.



        Touchscreen
        Touchscreen is the latest in the input devices where the input can be taken from
        the user through a touch of a finger, stylus or a light pen on a display screen. We
        can give the entire set of commands by touching. Nowadays most of the laptops,
        Smart TV, smartphones, tablets, etc. also have touch screens where the use of the
        keyboard is minimised. It is a very useful and convenient alternative to a mouse
        or a keyboard in a graphical user interface.
                                                                                              Touchscreen



                          Microphone

                          Microphone is a device that converts the sound received into a digital audio form which can be
                          easily stored or manipulated in a computer.
           Microphone



        Barcode Reader

        A bar code is a set of parallel lines that appear on the products as their identification.
        You will find most of the packages having these barcodes that can be easily read by
        barcode readers. Bar code readers work by placing a beam of light on the lines that
        make up the bar code and detecting the amount of light that is reflected back. The
        barcode read is then stored in the computer for preparing invoices.
                                                                                              Barcode Reader
        MICR

        The bank account number and other details are printed onto bank cheques which are
        read by Magnetic Ink Character Recognition using a special magnetic ink. They are
        useful to find out whether the cheque is genuine or fake.

                                                                                                   MICR
                 Processing Device—Central Processing Unit (CPU)

        After taking the input from the input devices, the information is sent for processing. The computer uses its brain
        to process the information. The computer’s brain is called the CPU or Central Processing Unit. CPU is basically
        divided into three parts:
                                 •  ALU stands for Arithmetic Logic Unit. It is responsible for all arithmetical and logical
                                 calculations.
                                 •  CU stands for Control Unit. It controls the flow of information in the system. The control
                                 unit is responsible for the flow of data from input devices to the processing unit and
                                 then to the output devices. It works like a traffic policeman who controls the traffic on
                                 the road.
                                 •  MU stands for Memory Unit. It is a storage unit that holds the processed or unprocessed
              CPU Chip           data.



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