# 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

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).

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etharijha likes this.

Apr 5, 2008
15,809
2,390
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
3,519
515
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
12,657
3,461
Next time please use a title that is more descriptive of the problem.