Solve Vx in Nodal Voltage Analysis

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Discussion Overview

The discussion revolves around finding the voltage Vx using nodal voltage analysis in a circuit. Participants are working through equations derived from the circuit diagram, addressing errors and clarifying relationships between voltages and currents.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant states they need one more equation to solve for Vx and lists known voltages: V1 = 4V and V3 = 2Vx.
  • Another participant points out an error in the equation presented, suggesting that the left side has units of Amps, which conflicts with the right side being a voltage.
  • Some participants discuss the correct formulation of the equation, with one proposing a revised equation that includes the correct relationships between the voltages and resistances.
  • A later reply confirms the correction and offers a new equation to help solve for V2, which is necessary for finding Vx.
  • One participant expresses gratitude for the clarification and acknowledges their oversight in understanding the equations.

Areas of Agreement / Disagreement

Participants generally agree on the need for a correct formulation of the equations but have differing views on the initial equation's validity and the interpretation of units involved. The discussion remains unresolved regarding the final solution for Vx.

Contextual Notes

There are unresolved issues regarding the assumptions made in the equations and the labeling of circuit elements, which may affect the clarity of the analysis.

Gclip5
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Homework Statement


Find Vx.
http://imageshack.com/a/img853/3093/ssdr.png

Homework Equations


NONE


The Attempt at a Solution


I just need one more equation so far I have:
1. V1 = 4v
2. V3 = 2Vx
3. (V1-V2)/2 = V2-V3+V2
 
Last edited by a moderator:
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Gclip5 said:

3. (V1-V2)/2 = V2-V3+V2

You made a error

(V1 - V2)/2Ω = V2/1Ω + ??
 
Last edited:
I don't see the error. The voltage is dropping across the resistor from V2 to V3. Likewise for the other one ohm resistor from V2 to ground.
 
Gclip5 said:

3. (V1-V2)/2 = V2-V3+V2

How can this be true if the left side of a the equation has a unit of Amps.
(V - V)/Ω = V/Ω = A
But on the right side you only have a voltage.
And as we all know Ampere are not equal to Volts
 
Jony130 said:
How can this be true if the left side of a the equation has a unit of Amps.
(V - V)/Ω = V/Ω = A
But on the right side you only have a voltage.
And as we all know Ampere are not equal to Volts

Well I guess the equation he meant to write is:

(V1-V2)/2 = (V2-V3)/1 + (V2-0)/1 which is equal to (V1-V2)/2 = V2-V3 + V2
 
Yeah sorry about the poor labeling, but Nugso is correct. I still can't figure out a third equation to get.
 
Ok I see the problem.
So all you need is this

(V1-V2)/2 = (V2-V3)/1 + (V2-0)/1 (1)

2Vx = V3 = 2(V1 - V2) (2)

And you solve for V2.
 
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THANKS. Can't believe i didnt see that.
 

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