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: Could anyone please help me with parallel-series circuit equations?

  1. Sep 23, 2009 #1
    This is the given

    I need to find those unknowns but I have no idea where as to even start.
    Any help would be appreciated, thanks alot
  2. jcsd
  3. Sep 23, 2009 #2
    Write down the Ohms's law, equations for calculating power P, and equations for adding resistors in series and parallel.
  4. Sep 23, 2009 #3
    To start with you need to look at what is given in terms of your resistors.
    For R1 you have PD and Power; and R4 you have Current and Power so use the formulas for power to find those resistances.
    R1 and R3 are in series; R2 and R4 are also in series
    To find the total resistance you will have to find the In Series Resistance first (Rs)and then you'll see that those subtotals will now be in Parallel to find the total Resistance Rt.
    If you review PD and Current for Resistors in Series and Parallel it will help you find the It and Vs
  5. Sep 24, 2009 #4
    Req=((R1+R3)*(R2+R4))/((R1+R3)+(R2+R4)); Req=Rt


    Itot=I1+I2; I1-----arm 1 current,I2-----arm 2 current;



Share this great discussion with others via Reddit, Google+, Twitter, or Facebook