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Homework Help: Electrical Circuit Calculations

  1. Oct 28, 2014 #1
    1. The problem statement, all variables and given/known data
    Calculate the individual currents in I2 and I3 (See diagram). I basically need to know how I calculate the current at any point in that circuit and that would help me.
    2. Relevant equations
    V=IR Rseries=R1+R2... 1/Rparallel=1/R1+1/R2

    3. The attempt at a solution
    I honestly have no idea how to calculate this, I think the current in I3 is 2A but really amn't sure. I know it's a simply ohms law question and I know the current splits between the resitors in parallel and it's inversely to do with the total resistance, but the fact there is so much going on in the circuit isn't helping me at all. Can anyone point me in the right direction? (I calculated the total resistance to be 24 ohms so the I drawn from supply would be 2A not even sure this is correct!)

    Attached Files:

    Last edited: Oct 28, 2014
  2. jcsd
  3. Oct 28, 2014 #2
    Bottom resistor which is cut off is 4 ohms.
  4. Oct 28, 2014 #3


    User Avatar

    Staff: Mentor

    Your current from the supply, ##I_1##, is correct. Use that to pencil in the voltage drops V1 and V3. That should lead you to the potential difference across R2+R3. That in turn allows you to calculate the portion of that 2 A that is diverted through R2+R3. Continue in that way, applying Ohm's law and Kirchhoff's laws to incrementally determine currents and voltages.
  5. Oct 28, 2014 #4
    Thanks! Just had a "light switching on moment" and it all makes sense now! Cheers :)
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