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Voltage drop and current through each resistor

  1. Apr 6, 2017 #1
    1. The problem statement, all variables and given/known data
    Determine the voltage drop and current through each resistor.

    *This is just my sketch of the problem since I couldn't take a clear picture of it.

    2. Relevant equations
    Ohm's law
    V= IR

    Parallel total resistance

    Series total resistance

    3. The attempt at a solution

    I'm having troubles understand what I should do when there's more than just a parallel or series in a circuit.

    If this were just a parallel problem then I would simply add up the resistors using the Req=1/R1+1/R2+1/R3+... equation and since I know that voltage is the same across a parallel circuit then I could simply solve for the total current (Ieq) by rearranging Ohm's law Ieq=V/Req from there I can figure out voltage drop and current through every resistor using V1=IeqR1, V2=IeqR2,... and I1=V/R1, I2=V/R2,...

    I would follow the same steps in a series circuit problem with the exception being that I would use Req=R1+R2+R3... instead of Req=1/R1+1/R2+1/R3+...

    Now, with my problem, I have both parallel and series. How should I go about doing this?

    I tried simplifying the circuit down and got an Req=14.6 ohms with the Voltage still being 10 volts. In this case would I use this Req value to calculate Ieq and just use that for the voltage drop and then just divide voltage by every resistor to figure out the current through each?

    Maybe I don't understand circuits correctly. I'm not sure. Any help/explanation is very much appreciated!
  2. jcsd
  3. Apr 6, 2017 #2


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    Homework Helper

    With the equivalent resistance you can calculate the current through the 6 ohm resistor and the parallel combination (the current would split up through the two branches of the parallel combination though).
    That means you can calculate the voltage over the 6 ohm resistor and the total voltage over the two parallel branches.
    Last edited: Apr 6, 2017
  4. Apr 6, 2017 #3
    Welcome to Physics Forums.

    A suggestion: When posting figures, you should use sufficient resolution so that the figure easily conveys all of the information. The values in your figure are simply not legible. For example, I would not have guessed the DC voltage to be 10 V - as you stated.
  5. Apr 6, 2017 #4


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    Gold Member

    +1 on that
    Neither would I since it clearly says 20v in the figure
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