Power generated by dependent source

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Discussion Overview

The discussion revolves around determining the power generated by a dependent source in a circuit, focusing on the application of circuit analysis principles. Participants explore various approaches to solving the problem, including the use of equivalent circuits and the passive sign convention.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • The initial attempt at a solution involves calculating the current and power using the formulas Ix=V/R and Pgen=V*I, but the poster expresses uncertainty about the correctness of their approach.
  • One participant suggests that the direction of the current Ix is opposite to that produced by the independent voltage source, indicating a need to apply a negative sign to the current's magnitude.
  • Another participant mentions that their professor provided clarity on the topic during class, suggesting that the textbook may not adequately explain the material.
  • A further contribution emphasizes the importance of recognizing that the wire connecting circuit parts cannot allow for both forward and return paths for current, leading to the conclusion that current in the middle wire must be zero.
  • Reference to a specific textbook, "Engineering Circuit Analysis by Hayt," is provided as a potential resource for further understanding.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and approaches to the problem, indicating that there is no consensus on the correct method to determine the power generated by the dependent source. Some participants provide corrections and alternative perspectives, suggesting ongoing uncertainty in the discussion.

Contextual Notes

There are limitations in the initial assumptions made regarding the circuit configuration, and the discussion reflects a dependency on the definitions and interpretations of circuit elements. Some mathematical steps remain unresolved, contributing to the uncertainty in the proposed solutions.

hogrampage
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Homework Statement


Determine the power generated by the dependent source in the circuit shown below:

blah-5.jpg


Homework Equations


Ix=V/R
Pgen=V*I

The Attempt at a Solution


I made an equivalent circuit, but it may not be correct (resistors in parallel?):

blah2-1.jpg


Ix=-(12V/(12/7)Ω)=-7A
2Ix=2(-7a)=-14A

Passive sign convention is satisfied for the dependent source, so Pgen = -Pabs:
Pgen=-(12V)(-14A)=-168W

I am not sure I did this correctly, as this is my first time in a class like this. If I am going about this wrong, could someone point me in the right direction? I understand most of the homework in this class, but this one kind of confused me.

Thanks
 
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I think you are straying way off course. The independent voltage source produces a current in that 3 ohm resistor. You can determine its value.

ix has a direction opposite to what the voltage source produces, so you need to attach a negative sign to the magnitude of the current and call it ix

continue ...
 
Yeah, my professor showed us how to do it in class today and it makes a lot more sense now. I had just learned the material and the book we have isn't very good at giving examples/explanations.
 
Yeah it can get tricky for a newbie but stick to basics...

First of all realize that the wire connecting the two parts of the circuit cannot provide for both forward and return path for current. So current in the middle wire has to be zero. Now analyse both the parts of the circuit individually following what nascent oxygen told in the previous post...

As far as a book is concerned you can refer to :
Engineering Circuit Analysis by Hayt
Best of luck
 

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