Need help solving E and I in a complex circuit.

Discussion in 'Homework Help' started by electronice123, Feb 7, 2010.

  1. electronice123

    Thread Starter Active Member

    Oct 10, 2008
    I need help solving the rest of this circuit. This is where I get stuck.

    Can someone explain step by step how to find E and I for R4,R5,R6,R7?

    I hope the picture is big enough to read.
  2. hobbyist

    Distinguished Member

    Aug 10, 2008
    R6 and R7 become a series resistor (R6,R7)
    this is in parrallel with R5,

    so so far it looks like this, R5 // (R6,R7)

    then this whole combo is in series with R4,

    so this all looks like this at this point,

    R4 in series with {R5 // (R6,R7)}.

    So once you have this calculated then you take this combo, and put it in parallel with the series (R2,R3), then put all that in series with R1, to get the total resistance, which alows you to solve for the totral current, then work from there to calculate the branch currents.
  3. PRS

    Well-Known Member

    Aug 24, 2008
    Something is wrong with the instructions. R4 and R5 are not in series. R6 and R7 are indeed in series, then they are in parallel with R5. And this result, R', is in series with R4 to get R''. R2 and R4 are, indeed in series, so add them and they are in parallel with R''. This results in R''' and this is in series with R1 so add. Now you can calculate the current through the equivalent circuit and using current division calculate the currents through the various branches. Try it, and then we can correct any mistakes.