What am I overlooking?

Discussion in 'Homework Help' started by DYLH, Oct 8, 2013.

  1. DYLH

    Thread Starter New Member

    Aug 13, 2013
    28
    1
    Please see the link: https://www.circuitlab.com/circuit/36b4ct/circuit-3-29/ or attached .png

    The loop at the top w/ the 2A current source... assuming the voltage meter VM2 is 'perfect' and draws no current, how can the current through R8 be anything other than 2A? Intuitively, I was expecting the voltage at VM2 to be 667mV.

    FWIW, originally the 'top' loop was flipped, and inside the larger loop... I thought I was clever for 'flipping' it outside to clearly see that the current through the loop couldn't be affected by other loops (e.g., using mesh analysis).
     
    etharijha likes this.
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,348
    Hello,

    The top line and bottom line both have a grounding mark on them.
    This will tell you they are connected.

    Bertus
     
    DYLH likes this.
  3. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,397
    497
    Additional current enters the R8 branch.

    If the R8 and 2 A current source were forming a loop, without any other connections, then yes, the current in the loop would have been 2 A. However, your R8+2 A current source loop is connected to another loop, that is where extra current comes from, looking at the ammeter in series with R8, the external loop provides 0.123 A.
     
  4. DYLH

    Thread Starter New Member

    Aug 13, 2013
    28
    1
    Hi Bertus - Yep, overlooked that! Was able to work it out.

    Small world, I'm actually taking a trip to Amsterdam this weekend to see Van Gogh and Ann Frank.

    Thanks again!
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Next time please use a title that is more descriptive of the problem.
     
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