How Do You Calculate Total Resistance?

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Discussion Overview

The discussion revolves around calculating total resistance in a circuit, specifically addressing a homework problem involving the arrangement of resistors. Participants explore different methods and transformations related to circuit analysis.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks verification of their answer to a homework problem regarding total resistance.
  • Another participant questions the definition of total resistance (RT) and suggests calculating voltages and currents for verification.
  • A participant challenges the assumption that two resistors, ##R_1## and ##R_2##, are in parallel, referencing a transformation from a delta (∇) to a wye (Y) configuration.
  • Another participant asserts that a specific answer of 6.22 Ohms is incorrect, citing reasoning from another participant.
  • The same challenge regarding the parallel arrangement of resistors is reiterated by a different participant, emphasizing the transformation in the circuit.
  • A later reply indicates improvement in the discussion or understanding, though specifics are not detailed.

Areas of Agreement / Disagreement

Participants do not appear to reach consensus, as there are multiple competing views regarding the configuration of the resistors and the correctness of the calculated total resistance.

Contextual Notes

There are unresolved assumptions regarding the circuit configuration and the application of the delta to wye transformation. The discussion lacks clarity on the specific circuit diagram being referenced.

Fatima Hasan
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Homework Statement



viber-image.jpg


Homework Equations


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R_b%3D%5Cfrac%7BR_a*R_b%7D%7BR_a+R_b%7D.gif


The Attempt at a Solution



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Could anyone check my answer please ?
 

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What is RT? What is the total resistance?

Usually an answer is easier to check than to get - calculate voltages and currents and see if they work out.
 
Why are you taking ##R_1## and ##R_2## to be in parallel? Here's what your circuit looks like after your ∇ to Y transformation:

upload_2018-10-26_9-55-37.png
 

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Just to be clear, your 6.22 Ohm answer is clearly wrong for the reason outlines by gneill.
 
gneill said:
Why are you taking ##R_1## and ##R_2## to be in parallel? Here's what your circuit looks like after your ∇ to Y transformation:

View attachment 232843
26%7D%5C%5C%5C%5C%3D6+%5Cfrac%7B15%7D%7B26%7D+%5Cfrac%7B609%7D%7B26%7D%3D30%20%5COmega.gif
 

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    26%7D%5C%5C%5C%5C%3D6+%5Cfrac%7B15%7D%7B26%7D+%5Cfrac%7B609%7D%7B26%7D%3D30%20%5COmega.gif
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Much better!
 
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