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: Parallel circuit problem

  1. Sep 12, 2014 #1
    1. Consider a circuit with 3 resistors (250.0 , 150.0 , 350.0  ) connected in parallel with a 24.0 V battery.

    Find the total current supplied by the battery.

    Find the current through each resistor.

    2. I=V/R

    3. I know that resistors in parallel must be added up and then inveted like so
    1/150 + 1/ 350 + 1/250 then invert the answer. When I do that I get 74. I then add that into I=V/R where V=24 and R=74
    My answer I=.324
  2. jcsd
  3. Sep 12, 2014 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    What you found is the current through the equivalent resistance. What they want is the current through each individual resistor. Do you know the voltage across each individual resistor? (hint: they are in parallel, so ...)
  4. Sep 12, 2014 #3


    User Avatar
    Homework Helper
    Gold Member

    Well, that's the total current through the battery, assuming the battery is ideal and does not have any internal resistance. :approve:

    The next part of the problem is to find the current through each resistor. (See nrqed's post)
  5. Sep 12, 2014 #4
    A shortcut to doing parallel resistance problems is to use the CONDUCTANCES of each component: (G=1/R). Then you can simply add the Gs of each component. This is what you're actually doing when you use the formular Rt=1/(1/r1+1/r2+1/r3.....). But they never tell you how they get that in most electronics classes!

  6. Sep 12, 2014 #5


    User Avatar

    Staff: Mentor

    With good reason, IMHO. It's too confusing! http://www.clicksmilies.com/s1106/waffen/violent-smiley-049.gif [Broken]
    Last edited by a moderator: May 6, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted