Page 69 - Electrician - TT (Volume 1)
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ELECTRICIAN - CITS




           Daniel cell: It is a modification of simple voltaic cell, because it is similar in chemical action. It was the first cell in
           which a depolariser was used to avoid polarisation and amalgamated zinc road for preventing local action.



















           Construction
           This cell consists of an outer copper vessel, which serves as positive electrode. This vessel contains concentric
           solution of copper sulphate, act as the depolariser. (this solution keep saturated by placing of crystal copper
           sulphate). In side this vessel is a porous pot containing dilute sulphuric acid as electrolyte and amalgamated zinc
           rod- act as negative plate.
           The chemical reaction inside the porous pot may be represented as follows;
           Zn  +H SO 4       ZnSO  + 2H
             ++
                  2
                                4
           The chemical reaction outside the porous pot is;
           2H + CuSO       H SO  +Cu ++
                     4      2  4
           In this manner polarisation is prevented.
           The EMF of the cell is1.12v and internal resistance varies from 2 - 6ohm.
           Advantages
           •  It is cheap and gives constant voltage

           •  So used in laboratories for experiment.
           Leclanche cell
           Construction
           This cell consists of a glass jar contain solution of ammonium chloride (NH Cl) as the electrolyte and amalgamated
                                                                           4
           zinc immersed it, as negative plate (fig) the fig also shows a porous pot containing a carbon rod as positive plate.
           This  pot  is  typically  packed  with  manganese  dioxide(MnO )  act  as  polariser  and  powdered  carbon  particles,
                                                                2
           serves as a conductor. A hole is provided at the top of porous pot for the gases escaping during chemical action.



























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                                    CITS : Power - Electrician & Wireman - Lesson 13-19
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