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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

    nrqed

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    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

    collinsmark

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    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!

    Eric
     
  6. Sep 12, 2014 #5

    NascentOxygen

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    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
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