Need help finding equivalent resistance in a circuit.

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Discussion Overview

The discussion revolves around finding the equivalent resistance in a specific circuit configuration, involving delta-wye transformations and the arrangement of resistors. Participants explore different approaches to simplify the circuit and calculate the total resistance.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant suggests using delta-wye transformations but feels uncertain about the next steps.
  • Another proposes treating pairs of 3 kΩ resistors as 6 kΩ resistors to simplify the circuit.
  • A participant considers the 6 kΩ resistors as being in parallel and calculates an equivalent resistance of 4.8 kΩ for part of the circuit.
  • There is a challenge regarding the accuracy of the previous calculations and the importance of identifying the correct nodes in the circuit.
  • One participant outlines a method to treat the resistors in parallel and series, arriving at a total resistance of 16.8 kΩ, while seeking clarification on potential mistakes.
  • Another participant emphasizes the need to find the resistance specifically between nodes A and B, indicating the importance of maintaining the A node in the calculations.

Areas of Agreement / Disagreement

Participants express differing views on the correct approach to calculating the equivalent resistance, and the discussion remains unresolved with multiple competing methods and interpretations presented.

Contextual Notes

There are uncertainties regarding the identification of nodes and the specific configuration of resistors, which may affect the calculations. Some assumptions about resistor arrangements and transformations are not explicitly stated.

Who May Find This Useful

Students working on circuit analysis, particularly those dealing with equivalent resistance calculations and delta-wye transformations.

naivy
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Homework Statement



nTqaP.png


Homework Equations



delta wye transformations?

The Attempt at a Solution



PM9Qm.png

I feel like I should do delta wye transforms here, but that doesn't really lead me anywhere. Am I missing how I should do the problem?
 
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Perhaps if you treated the two pairs of 3 kΩ resistors as two 6 kΩ resistors, you would realize the next step.
 
Oh, wait... treat them as 6 kΩ resistors and then they become resistors in parallel?

In that case, does the whole half above A become equivalent to 4.8 kΩ? If so, then the whole circuit would have an equivalent resistance of 14.4 kΩ? Is that right? Or did I take your hint the wrong way...
 
Your thinking and answer was wrong.

What is each 6 kΩ in parallel with?

Where is A?
 
So I figured the following:

wQWD1.png


Treat the boxed resistors as 6 kΩ and then treat those to be in parallel with the 4 kΩ resistors under them.

Then we can treat the two pieces on the top (the two sets of parallel resistors) to be parallel with each other and be equivalent to 4.8 kΩ.

The region I'm thinking of as being equivalent to 4.8 kΩ is shown in the circle below.

QcQkN.png


Then, we can just treat the 4.8 kΩ to be in series with the other four 3 kΩ resistors to get an answer of (4.8 kΩ + 12 kΩ) 16.8 kΩ.

Can you please guide me as to where I messed up? Thank you so much for your help!
 
You're supposed to be finding the resistance between A and B. You have to keep the A node!
 
BGHCy.jpg
 
That's correct.
 

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