Finding V-I Characteristic of Circuit

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Discussion Overview

The discussion revolves around finding the voltage-current (V-I) characteristic of a given electrical circuit. Participants explore the implications of the circuit's configuration and the known parameters, including resistances and voltage supply, while addressing potential ambiguities in the circuit diagram.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks guidance on deriving the V-I characteristic, expressing confusion about the relationship between voltage and current in the context of the circuit's resistance.
  • Another participant questions the meaning of finding the V-I characteristic, suggesting that the voltage supply allows for straightforward calculations of V and I.
  • Some participants express uncertainty about the circuit diagram, particularly regarding the purpose of the ground and the configuration of the components, questioning if it is intentionally misleading.
  • There are suggestions to analyze the circuit in segments, proposing to consider sub-circuits and their characteristics, while others clarify that the original poster's question was not about circuit analysis itself.
  • One participant indicates a desire to avoid excessive specificity in addressing potential issues with the circuit sketch, suggesting a lack of engagement from the original poster.

Areas of Agreement / Disagreement

Participants generally express uncertainty and confusion regarding the circuit's configuration and the role of the ground. There is no consensus on whether the circuit is correctly drawn or if something is missing, and multiple views on the interpretation of the V-I characteristic remain present.

Contextual Notes

Some participants note that the circuit may have been drawn incorrectly or that important details might be missing, which could affect the analysis. The discussion includes varying interpretations of the circuit's layout and its implications for deriving the V-I characteristic.

abeltyukov
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Hi,

I have the following circuit: http://i137.photobucket.com/albums/q208/infinitbelt/ProblemSet3Circuit1.png"

Also, the following is known:
X=60 V
R1= 10 Ω
R2= 20 Ω
R3= 10 Ω
R4=5 Ω
R5=20 Ω
R6 = 5 Ω

How do I go about finding a V-I characteristic of this circuit? I know that the slope of the graph is the resistance but I am confused as to how to start this one. I found the resistance across the source by using circuit reduction. I got that to be 32 ohms. So is the V-I characteristic just V = 32i? or is it just a constant line y = 60? (in this case V is on the y-axis and I is on the x-axis)


Thanks!
 
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What exactly do you mean find the V-I characteristic? Your battery supply is 60V and you already can solve for V and I.
 
Corneo said:
What exactly do you mean find the V-I characteristic? Your battery supply is 60V and you already can solve for V and I.

If you vary the voltage V, what is the variation of the current I?
The question was also posed at the homework forum, so it should be deleted from this forum.
 
Is something missing or perhaps drawn incorrectly? The problem looks odd and I can't figure out the purpose of that ground (just something to throw you off?).
 
TVP45 said:
Is something missing or perhaps drawn incorrectly? The problem looks odd and I can't figure out the purpose of that ground (just something to throw you off?).

The ground has no meaning at all, since the input V is taken across R5.
 
Well, I think I agree that the ground has no meaning, but why is it there? Is this just supposed to be tricky? And, why the very strange configuration of R1, R3, and X? Again, is this just tricky, or is something missing?
 
TVP45 said:
Well, I think I agree that the ground has no meaning, but why is it there? Is this just supposed to be tricky? And, why the very strange configuration of R1, R3, and X? Again, is this just tricky, or is something missing?
R1, X and R3 are in series (forget the ground), so you can draw the characteristic of this sub circuit (call it I).
I is in parallel with R3 and you can draw the characteristic of this new sub circuit (call it II).
II is in series with R4 and R6 (call this sub circuit III).
Finally III is in parallel with R5.
 
CEL said:
R1, X and R3 are in series (forget the ground), so you can draw the characteristic of this sub circuit (call it I).
I is in parallel with R3 and you can draw the characteristic of this new sub circuit (call it II).
II is in series with R4 and R6 (call this sub circuit III).
Finally III is in parallel with R5.

I know how to do circuit analysis; that wasn't my question.
 
TVP45 said:
I know how to do circuit analysis; that wasn't my question.

What is your question then?
 
  • #10
My question was: Is something missing from the sketch? I don't want to be too specific or linger too much on this since we've perhaps lost the OP - no attempt at work yet. I'll send you my comments by private message and get off this thread.
 

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