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Voltage in series and parallel circuits

  1. Feb 1, 2012 #1
    Why is it that in a series circuit the sum of the voltages across the components is equal to the voltage supplied by the battery but in parallel the voltages are equal for different branches in the circuit?
  2. jcsd
  3. Feb 1, 2012 #2


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    hi johnathon! :smile:
    because the voltage between any two points does not depend on the path taken :wink:
  4. Feb 1, 2012 #3


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    I must not be understanding your question because to me your question sounds exactly like "why is the voltage across a battery equal to the voltage across the battery"
  5. Feb 1, 2012 #4
    What I was asking is if there're three branches, why isn't the voltage accross each branch equal to 1/3 of the supplied voltage?
  6. Feb 1, 2012 #5


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    Because the voltage across the battery is the voltage across the battery. What you hook up to it is irrelevant (other than a short circuit).
  7. Feb 1, 2012 #6


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    Hi johnathon

    have a look at this circuit....


    Q --what do you notice about points 1,2,3 and 4 ?

    A -- They are all connected in common to the positive terminal of the battery
    just as points 5,6,7 and 8 to the negative terminal
    The fact that they are all commoned, means that they MUST be at the same voltage potential

    Now with the current flowing in the circuit thats different. Because the resistors are of different values, the current flow through each resistor will be different
    knowing the voltage across and the value of each resistor you can use Ohms Law and work out the current flowing through each resistance branch
    and therefore the total current flowing in the circuit. The total current will be equal to the sum of the flow through each resistor.


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  8. Feb 1, 2012 #7


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    In circuit diagrams, conductors are treated as perfect conductors (zero resistance), so the voltage at any point on an idealized conductor is constant.
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