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Potential difference across capacitor

  1. May 9, 2017 #1
    • Member advised to use the homework template for posts in the homework sections of PF.
    Hi, the solution of my exercise says that the potential difference in the capacitor C1 is zero. 1494361264-screenshot-from-2017-05-09-16-06-36.png
    Can you please explain me why it's the case ?

    Thank you.
     
  2. jcsd
  3. May 9, 2017 #2

    scottdave

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    Homework Helper
    Gold Member

    You don't have any values for those capacitors. This is an example of a bridge circuit. Read this article for some insight. https://en.wikipedia.org/wiki/Bridge_circuit

    Resistors and capacitors work differently, but be assured that there are capacitor values which would result in the voltage at the top of the C1 to be the same voltage as the bottom of C1. For example, if we have 10.5 volts at the top and 10.5 volts at the bottom, then 10.5-10.5 = 0.
     
  4. May 9, 2017 #3
    Owwww I'm sorry, I forgot to give the values !!

    In fact, we have C2=C4 = 1.0μF and C3=C5 = 2.0μF.
     
  5. May 9, 2017 #4
    However what if, in this case, we have C2 =/= C4 OR C3 =/=C5, C1 wouldn't be equal to zero anymore, right ?
     
  6. May 9, 2017 #5

    berkeman

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    Staff: Mentor

    Correct.
     
  7. May 9, 2017 #6

    scottdave

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    You should really take a look at the article on Bridge circuits, which I pointed to in the earlier post. Once you understand how resistor bridge circuits work, it will not be much of a stretch to understand other components, such as capacitors.
     
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