Page 46 - Electrician - TT (Volume 1)
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ELECTRICIAN - CITS



           Application of parallel circuit

           An electrical system in which one section can fail and other sections continue to operates as parallel circuits. The
           electric system used in homes consist of many parallel circuits.
           An automobile electrical system uses parallel circuit for lights, horn, radio etc.

           Comparison between series and parallel circutit
             Sl No    Series Circuit                             Parallel Circuit

              1       The sum of voltage drops across the   The applied voltage is the same across each branch
                      individual resistance equals the applied
                      voltage
              2       The total resistance is equal to sum   The reciprocal of total resistance equals the sum
                      of the individual resistance that make    of the reciprocal of the resistances. The resultant
                      up the circuit                       resistance is less than the smallest resistance of
                                                           the parallel combination

              3       Current is same in all parts of      Current divides in each branch according to the
                      the circuit                          resistance of each branch
              4       Total power is equal to the sum of   Same as series circuit.
                      the power dissipated by the
                      individual resistances


           Series parallel combination of resistance (Fig 19)
           A part of series and parallel circuit form in a single circuit is known as series parallel combination circuit. A series
           parallel combination appears to be very complex circuit

           The two basic arrangement of two series parallel circuit is shown in figure.

              Fig 19

















           Application

           Series-parallel circuit be can be used to form a specific resistance value which is not available in the market and
           can be used in the voltage divider circuits
           Classification of resistance

           Low resistance
           •   1 ohm and below 1 ohm
               Example-Armature winding, ammeter shunt, contact resistance
           Method used for the measurement
           •  Kelvin double bridge

           •  Ammeter voltmeter method
           •  potentiometer method


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                                    CITS : Power - Electrician & Wireman - Lesson 5 - 12
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