What is the voltage in the circuit?

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    Circuit Voltage
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Discussion Overview

The discussion revolves around solving a circuit problem involving voltage calculations using different methods, specifically loop analysis and nodal analysis. Participants share their approaches and results while seeking verification and corrections from others.

Discussion Character

  • Homework-related
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant claims to have calculated V0 as 12.5292V and requests verification of their answer.
  • Another participant presents a nodal analysis approach, arriving at a different voltage of +14.359V, expressing a preference for nodal equations over loop equations.
  • A third participant questions the correctness of the nodal equation provided, suggesting a missing consideration of a resistor in the analysis.
  • The second participant acknowledges the feedback and agrees to recompute their equations.
  • After recomputing, the second participant reports a new voltage of +13.12V and shares their equations for further review.
  • A later reply confirms that they also arrived at +13.12V after revisiting their loop equations, indicating a potential alignment in results.
  • Another participant expresses enthusiasm for the collaborative effort in solving the problem.
  • A participant requests additional help on a different question, indicating a desire for further assistance with their loop analysis work.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct voltage value, as multiple competing results are presented. The discussion remains unresolved with differing methodologies and outcomes.

Contextual Notes

Participants express uncertainty about their equations and calculations, indicating potential errors and the need for further verification. There are also differences in preferences for analytical methods (nodal vs. loop analysis) that may influence the results.

ee_ess_ee-kid
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Homework Statement



http://i.imgur.com/YRK5L.png

Homework Equations



Loop analysis, so KVL

The Attempt at a Solution



I did the problem, and I got V0 = 12.5292V. If this is incorrect, I'll be more than happy to upload my work. Can someone verify the answer for me? Just tell me if it's right or wrong.
 
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I got Vo+ - Vo- = +14.359 V.

I use nodal equations rather than loop equations. I've always thought loop equations were stupid. I just pick every independent node and sum currents = 0. For example, my first (of three) equation is

(10 - Vx)/2K + (Vo+ - Vx)/3K + 8mA = 0.
Vx is the voltage in the middle. I made the bottom node zero V. (I really should have made Vo- = 0 but it doesn't matter).

I don't want to look at your loop equations, for which I apologize. I just don't like it when one component can carry 2 or 3 or even more "currents"!

BTW I used math app software to do the equation solving so my answer is correct assuming I wrote the equations right. I checked carefully but they could still be wrong, of course.
 
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It seems like your example nodal equation is for the middle node, in which case, I think it looks incorrect?

If it is the middle node, you forgot to consider the 2k resistor to the right of the node.
 
You are absolutely right!

I will recompute. Thanks for bringiong that to my attention.
 
Now I get +13.12V.

Here are my three equations, maybe you can spot another mistake. Don't be confused by the fact that I use conductances instead of resistances: G = 1/R. It makes the math easier for me. Conductances are in mS, currents in mA (1mS = 1/1K ohm):

0.5(10-x) + .33333(Vop-x) + 8 + 0.5(Von-x) = 0
4 = 0.33333(Vop-x) + 0.125(Vop-Von)
0.125(Vop-Von) + 0.5(x-Von) = 0.125Von
 
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rude man said:
Now I get +13.12V.

Here are my three equations, maybe you can spot another mistake. Don't be confused by the fact that I use conductances instead of resistances: G = 1/R. It makes the math easier for me. Conductances are in mS, currents in mA (1mS = 1/1K ohm):

0.5(10-x) + .33333(Vop-x) + 8 + 0.5(Von-x) = 0
4 = 0.33333(Vop-x) + 0.125(Vop-Von)
0.125(Vop-Von) + 0.5(x-Von) = 0.125Von

Awesome, I tried doing the problem again and it seemed like I missed something in my loop equations as well. I got 13.12 V too.
 
Could you possibly look at my other question please?

https://www.physicsforums.com/showthread.php?t=539166"

It uses loop analysis, which I know you said earlier that you dislike, but primarily I'd like to know if my answer is correct. Thanks.

In the best case scenario, you could maybe point out my error in my work. I put all of my equations in the post. Thanks again for your help on this problem!
 
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