0.1A discrepancy when summing currents in parallel circuit

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5 replies · 2K views · last reply
Mark Nussbaum

Homework Statement


Circuit schematic of a single node pair with resistors R1, R2, R3 and R4, a current source is, a dependent current source of 0.5 Vx, and currents i1 through i5 marked by arrows along branches above and below the line.


Homework Equations


V=IR
parallel resistance.

The Attempt at a Solution


All elements are in parallel (teacher confirmed this in explanation to the class). Beginning placing labels for nodes to the right of R1, A, B, C, D, and E (ending before R4) and redrawing it as the teacher showed to get us started...
Handwritten circuit analysis on paper: small schematic of resistors R1 to R4 with nodes A to E and dependent source Vx, above KCL and Ohm's law equations solving for Vx, I5 and branch currents i1 to i3.

Once I add the currents together in the original equation I end up with .1A left over...
(sorry about low quality don't know how to get it to a webpage.)
 
Attachments
  • Handwritten circuit schematic with nodes A to E and resistors R1 to R4 plus a voltage source, next to handwritten KCL and Ohm's law calculations giving currents of about 0.5527 A, 0.1023 A, 0.2126 A and 0.1043 A.
    upload_2017-9-16_2-49-32.png
    88.5 KB · Views: 619
  • Handwritten circuit diagram with nodes A through E and resistors R1 to R4, plus a meter, beside Kirchhoff current law and Ohm's law working; the total evaluates to Vx = 11.05585 V.
    upload_2017-9-16_2-51-15.png
    88.6 KB · Views: 618
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Discussion

Mark Nussbaum, are you still working on this? You know the current from the .5 Vx source and you know the current through R4 (it's the same as I5); do you see how those two allow you to calculate I4?