Circuit Analysis Question -- 2 sources and 4 resistors

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Homework Help Overview

The discussion revolves around a circuit analysis problem involving two sources and four resistors, with a specific focus on applying the principle of power supplied equating to power absorbed. Participants are exploring the implications of using Kirchhoff's Voltage Law in this context.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the setup of the equations for power supplied and absorbed, questioning the validity of their calculations and the interpretation of variables used. There are inquiries about the relationship between the dependent source and the known current.

Discussion Status

The conversation is active, with participants providing insights and corrections regarding the use of variables in equations. Some are questioning the assumptions made in the problem setup, while others are attempting to clarify the relationships between the components involved.

Contextual Notes

There is mention of specific values for currents and voltages in the circuit, as well as a perceived complexity in the problem that may not align with the expected approach. Participants are navigating through potential misunderstandings regarding the dependent source and its influence on the overall circuit analysis.

jisbon
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Homework Statement
As shown below.
Relevant Equations
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1586331720640.png

Now, I know this question can be solved using Kirchoff Voltage rule, but the question expliciitly wants me to use power supplied = power absorbed. Hence taking V0 to be x, I can't still seem to calculate. Any ideas?

Power supplied = (60)(3) + (5x)(3) = 180+15x
Power absorbed = 72+ 56 +28 + 3x

``180+15x = 72+ 56 +28 + 3x
x =2 which is obviously wrong. Any ideas?
 
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The dependent source voltage is 5IO. IO is known.
 
Last edited:
Is there something wrong with this exercise ? I see 30 V on the left and then 12 V over the top left resisitance.
So the 1`8 V is a giveaway !

I suppose that is what the OP means with
jisbon said:
I know this question can be solved using Kirchoff Voltage rule
But why come up with a 'hint' (that is perceived as force) that needs a lot of calculation ?
 
Good point, BvU. I too, had fallen victim to the Jedi mind-trick.
 
jisbon said:
Power supplied = (60)(3) + (5x)(3) = 180+15x
Power absorbed = 72+ 56 +28 + 3x

``180+15x = 72+ 56 +28 + 3x
x =2 which is obviously wrong. Any ideas?
You used x for I0 in the top equation and x for V0 in the bottom equation.
 
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phyzguy said:
You used x for I0 in the top equation and x for V0 in the bottom equation.
Hmm seems like you are correct. But with now having two separate variables, how do I solve them now?
``180+15y = 72+ 56 +28 + 3x where y is I0 and x is V0
 
lewando said:
The dependent source voltage is 5IO. IO is known.
I0 is 3A right? So wouldn't the power be (5*3)A *V0?
 
IO is 2A as indicated (at the top of the circuit). Why do you think VO has anything to do with the power supplied by the dependent voltage source?
 
lewando said:
IO is 2A as indicated (at the top of the circuit). Why do you think VO has anything to do with the power supplied by the dependent voltage source?
Sorry for being careless wow :/ Got the answer too, thanks
 

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