1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Calculating the Current in a Two battery Combination Circuit

  1. Feb 27, 2012 #1
    1. The problem statement, all variables and given/known data

    For the circuit shown in the figure below, calculate the current I4 through the 1.94Ω resistor.
    As shown, R1 = 4.05Ω, R2 = 8.11Ω, R3 = 6.17Ω, R4 = 1.94Ω, I1 = 2.97A and E1 = 12V

    2. Relevant equations
    ƩI in a junction = ƩI out of a junction
    ƩV in a loop = 0

    3. The attempt at a solution
    I1R1+I1R2 -E1 + I2R3 =0
    I1 = I2 + I4
    I4 =I1 - ((-(I1*R1) - I1R2 + E1)/R3)

    I don't have many tries left, so I want to know if my analytical solution is correct, and if I've just been making my error plugging the numbers back in.
  2. jcsd
  3. Feb 27, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi BornSurvivor! :smile:
    looks ok so far

    but won't you need an equation involving E2 ? :confused:
  4. Feb 27, 2012 #3
    Nope! Those two equations were all I needed. It turns out I had mixed up the numbers for R2 and R3. :)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook