Equivalent Resistance of Cube of Resistors: A to B

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Homework Help Overview

The problem involves determining the equivalent resistance of a cube of resistors, each with a resistance value of "R", specifically between points A and B. The discussion centers around the validity of a proposed equivalent circuit presented in a textbook.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants question the accuracy of the textbook's parallel combinations and suggest that symmetry may play a role in the circuit's configuration. Some express uncertainty about the correctness of the proposed solution.

Discussion Status

The discussion includes various perspectives on the symmetry of the circuit and its implications for the equivalent resistance. While some participants express skepticism about the textbook's approach, others acknowledge the potential validity of the symmetry argument. There is no explicit consensus reached among participants.

Contextual Notes

Participants note that the original problem has been discussed in the past, and there are references to previous threads and simulations related to the topic. The discussion reflects a mix of current and historical perspectives on the problem.

nil1996
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Homework Statement


Here is a cube of resistors with each resistance of value "R".Find the equivalent resistance between A and B.

attachment.php?attachmentid=66606&stc=1&d=1392346578.jpg


Homework Equations


The Attempt at a Solution



My book says the equivalent circuit of the cube is :

attachment.php?attachmentid=66607&stc=1&d=1392346578.jpg


But i don't think it is correct.They have made parallel combinations which don't seem right.Is the book correct??
 

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you need to make your figures smaller. They are HUGE.

I agree w/ you that it doesn't seem correct but I'm guessing they are using some trick of symmetry in the redrawing.
 
The plane through the points ABGH is a symmetry plane, so the potentials of the points D and E must be equal, so you can connect them with a wire. Same for the points C and F.
 
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willem2 said:
The plane through the points ABGH is a symmetry plane, so the potentials of the points D and E must be equal, so you can connect them with a wire. Same for the points C and F.

O,thanks a lot :smile:
 
nil1996 said:

Homework Statement


Here is a cube of resistors with each resistance of value "R".Find the equivalent resistance between A and B.

View attachment 167327

Homework Equations


The Attempt at a Solution



My book says the equivalent circuit of the cube is :

View attachment 167328

But i don't think it is correct.They have made parallel combinations which don't seem right.Is the book correct??
I realize this is a decade old thread but I checked it and it is correct.
 
Last edited:
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bob012345 said:
I realize this is a decade old thread but I checked it and it is correct.
I thought of your simulations when I saw this thread pop up! :smile:
 
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