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Homework Help: Voltage Division

  1. Jul 3, 2008 #1

    I guess I do not understand voltage division properly can someone see why this doesnt work.

    Why is the first one giving the wrong answer..?


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  3. Jul 3, 2008 #2


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    Staff: Mentor

    Yes, you have to combine the two parallel resistors into their equivalent resistance. Why did you ignore the 20 Ohm resistor in your first attempt?
  4. Jul 3, 2008 #3


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    Homework Helper

    It's true that the voltage drop across parallel circuit elements are always the same, but the voltage division principle is not based on that. Rather it's based on the conservation of current though 2 circuit elements in series. You have to find the equivalent resistance for the two elements because the 5 ohms is not in series with the 4 ohms.
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