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!

Circuit analysis current source problem

  1. Nov 15, 2015 #1
    1. The problem statement, all variables and given/known data
    given the circuit shown, find V1.
    12231610_1652042151703604_2077339994_n.jpg
    2. Relevant equations


    3. The attempt at a solution
    see image:
    am i right? Video says otherwise... I chose to use the superposition theorem here.
    12200761_1652042148370271_1013343203_n.jpg

    help appreciated,

    regards,

    james.
     
  2. jcsd
  3. Nov 15, 2015 #2

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    That second image is very difficult to read.

    It appears that you took the 80Ω and 120Ω to be a parallel combination, which is correct. However, that combination is NOT in series with the 8Ω resistor.
     
  4. Nov 15, 2015 #3
    I think they're considered in series for getting the current through them when the 1A supply is ignored, but must be separated to get individual resistor voltage drops. Once all individual voltage drops are gotten they are then combined (superpositioned?) for the answer.
     
  5. Nov 16, 2015 #4
    surely this is correct?
    12242271_1652116441696175_986558241_n.jpg
     
  6. Nov 16, 2015 #5

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    That's fine for the 6A source.

    There is a different parallel/series combination you need to use for the 1A source. For this, there is no 56Ω combination.

    (Thanks, insightful.)

    Added in Edit:
    The above refers to the following:
    upload_2015-11-16_7-56-6.png

    The 40Ω and 8Ω are in series.
    That combination and the other two resistors, 80Ω and 120Ω, are all in parallel with the other.
     
    Last edited: Nov 16, 2015
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Circuit analysis current source problem
Loading...