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: Tips for analyzing a combination circuit

  1. Mar 7, 2009 #1
    1. The problem statement, all variables and given/known data
    So this Monday I will have a test, and I know for a fact that one of the free response questions will be a circuit with a combination of series and parallel resistors.So my question is can you guys give me some tips on how to do these successfully. I know that I need to start from the farthest resistor. In parallel the voltage is the same, and throughout the circuit the voltage is the same for the series ones. Any more things I need to now? also I don't understand really when there are 2 batteries in the circuit.
  2. jcsd
  3. Mar 7, 2009 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    One tries to simply the resistances into equivalent resistances.

    Parallel components share the same voltage (potential) since they share common nodes, but series resistances have the same current, and the voltage drop would be the same only if the resistances are the same.

    A battery raises the potential from - terminal to + terminal when the current i is oriented from - to +, and lowers the potential when the current i is oriented against + to - terminal.

    i.e. if i -> then - || + raises potential, and lowers it if the battery is oriented + || -
  4. Mar 7, 2009 #3
    In cases where all resistances can be simplified to series and parallel, it's sometimes helpful for a beginner to write the combination in words, then look at the picture again to verify it. A person might write something like:

    [ (R1 series R2) parallel (R3 series R4) parallel R5 ] series R6

    ... then check it by another look at the diagram. If it still looks right, proceed with the calculations.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook