Electrical circuit related problem

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Discussion Overview

The discussion revolves around a homework problem involving an electrical circuit, specifically determining the voltage Vx across a 3A current source. Participants explore the application of Kirchhoff's Voltage Law (KVL) and the implications of voltage source polarities in their calculations.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant expresses confusion about how to determine the voltage Vx and suggests calculating the voltage across a 4 ohm resistor first.
  • Another participant agrees with the initial approach and recommends using KVL around the left loop to find the voltage.
  • There is uncertainty regarding the assignment of positive and negative values to the voltage sources, with one participant questioning whether to assume the larger voltage source is positive.
  • A later reply clarifies that the voltage sources are labeled with their polarities, indicating that guessing is unnecessary and that a systematic approach using KVL should be followed.

Areas of Agreement / Disagreement

Participants generally agree on the use of KVL to solve the problem, but there is some initial uncertainty regarding the treatment of voltage source polarities. The discussion does not reach a consensus on the specific approach to take before the clarification is provided.

Contextual Notes

Participants rely on the labeling of voltage sources for polarity, and there is an assumption that the circuit diagram is available for reference, which may influence their reasoning.

Yammy
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Homework Statement



Determine the value of the voltage Vx
across the 3A current source.

Homework Equations





The Attempt at a Solution


I am really confused about how to do it. What I thought of is to find the voltage across the 4 ohm resistance which is 12 V. I though of subtracting that from the power sources.

But I am not sure which power source should be positive and which one should be negative?
Should I just assume the bigger 6V to be positive just because it is the bigger power source?
I might be completely wrong on this one. So please help me. This is not really a homework problem, this is in one of my practice tests, so I would appreciate any proper explanation I can get, rather than vague hints.
Thank you.
 

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Oh and please look at the attachment for the diagram
 
Yammy said:

Homework Statement



Determine the value of the voltage Vx
across the 3A current source.

Homework Equations





The Attempt at a Solution


I am really confused about how to do it. What I thought of is to find the voltage across the 4 ohm resistance which is 12 V. I though of subtracting that from the power sources.
Sure, sounds like a good idea. Use KVL around the left loop.
But I am not sure which power source should be positive and which one should be negative?
Should I just assume the bigger 6V to be positive just because it is the bigger power source?
The voltage sources are labeled with their polarities so no need to guess! Just do a "KVL walk" around the loop in either direction and sum up the potential changes as you go. The math will take care of itself.
 
ya u r right. Got it and thanks a lot.
 

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