Finding a voltage across 2 nodes [Check answer - work already done]

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Discussion Overview

The discussion revolves around determining the voltage across two nodes in a circuit analysis problem. Participants are reviewing calculations and assumptions related to Kirchhoff's Voltage Law (KVL) and the configuration of the circuit, including the presence of multiple loops.

Discussion Character

  • Homework-related
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • The original poster (OP) claims to have calculated V1 as 18V but does not provide sufficient context or explanation for their solution.
  • One participant requests the OP to clarify the original question and provide a more detailed solution, suggesting the use of KVL.
  • Another participant presents an alternative calculation, arriving at V1 = 37.33V and Vx = 13.33V, asserting that these values check out with the schematic.
  • Concerns are raised about the implications of having two loops in the circuit, with one participant suggesting that if there are indeed two loops, V1 would equal 0.
  • Another participant agrees that two loops seem likely but questions the validity of the OP's calculations, noting that the OP's finite value for V1 contradicts this assumption.
  • Discussion includes speculation about the design of the problem, with suggestions that it may be a trick question rather than a straightforward circuit analysis problem.

Areas of Agreement / Disagreement

Participants express differing views on the number of loops in the circuit and the implications for the voltage calculations. There is no consensus on the correct value of V1 or the overall approach to the problem.

Contextual Notes

Participants note potential ambiguities in the problem setup, including the lack of clarity regarding the circuit diagram and the presence of signs indicating voltage levels. These factors contribute to the uncertainty in the calculations and interpretations.

naivy
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Homework Statement



blFU9.png


Homework Equations





The Attempt at a Solution


I got V1=18V
Here's my work:
AdrND.jpg
 
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Can you repost the original question and then rewrite your solution with some brief explanations to show what you are doing? i.e KVL (Right): V1 - Vx - 24 = 0
 
I got V1 = 37.33V, Vx= 13.33V. It checks when you plug the numbers into your schematic.

If V1 = 18V then Vx = 18 - 24 = -6V so i thru the 25K = -6/25 = 0.24 mA
whereas i thru the 5K would then be
(-3*6 - 18)/5 = -7.2 mA so that can't be right.
 
Vab = Va - Vb. Assuming Va is at V1+ and Vb is at V1-, what is V1?

Given V1, and using KVL around the right hand loop, what is Vx?
 
There are 2 loops? If so, V1 = 0!
 
Given the line drawn between V1+ and V1-, and the node 'dots', it seems a safe assumption that there are two loops, rather than just one with an errant line.

I got V1 = 37.33V, Vx= 13.33V. It checks when you plug the numbers into your schematic.

I did it your way as well though and got the same numbers, but wanted the original question reposted just to verify.
 
Two loops were my firat assumption too, but then I realized that that would make the problem pathological (viz. V1 = 0). Also, the OP calculated a finite (albeit erroneous) V1. So I decided that extra line must indicate voltage rise gnd to V1, although I did wonder why there was no arrow at the top of that line. Also, if two loops, why did the OP have - and + signs next to that line?
 
Also, if two loops, why did the OP have - and + signs next to that line?

It could possibly have been designed as a (trick) knowledge problem, rather than a circuit analysis problem. Needs more OP confirmation I suppose.
 

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