Find Equiv. Resistance of Circuit: R1, R2, R3, R4

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Discussion Overview

The discussion revolves around finding the equivalent resistance of a circuit involving multiple resistors (R1, R2, R3, R4) arranged in a complex configuration. Participants explore different approaches to analyze the circuit, including series and parallel combinations.

Discussion Character

  • Homework-related
  • Exploratory
  • Technical explanation

Main Points Raised

  • One participant expresses confusion about how to approach the circuit due to its complex connections, noting that R1 and R2 are in series but connected to R3 and R4 in multiple places.
  • Another participant suggests following the path from the power source around the circuit, indicating that there are no resistors in that path.
  • A participant proposes that R1 and R2 could be in parallel with R3 and R4, suggesting a formula of (R1 + R2)||(R3 + R4).
  • One participant claims that a continuous path around the resistors short-circuits them, resulting in zero resistance, although this is later challenged.
  • After realizing a mistake in their circuit drawing, a participant presents a revised circuit and questions whether the equivalent resistance could be calculated as (R1||R4)+(R2||R3), indicating a belief that R1 and R2 are in series while R1R4 and R2R3 are in parallel.
  • Another participant confirms that the top two resistors are in parallel and the bottom two are also in parallel, with the two parallel parts in series.

Areas of Agreement / Disagreement

The discussion reflects uncertainty and multiple competing views regarding the arrangement of the resistors and the correct approach to calculating the equivalent resistance. No consensus is reached on the final solution.

Contextual Notes

Participants express confusion about the circuit configuration, and there are unresolved assumptions about the connections between the resistors. The discussion includes different interpretations of the circuit layout.

Atlos
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Homework Statement


I'm just trying to find the equivalent resistance of this:
http://sogacity.com/images/circuit.png


Homework Equations


Resistors in series add and resistors in parallel inversely add.


The Attempt at a Solution


I'm not even sure how to approach this. I guess I can't get my head around how it is set up. R1 and R2 are in series, but being connected to R3 and R4 in multiple places is what's confusing me. If somebody could help me create an equation for the equivalent resistance of all of that I would be thankful.
 
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Follow the path from the power source around the outside of the drawing. No resistors.
 
Do you mean like this?

http://sogacity.com/images/circuit2.png

So would R1 and R2 be in parallel with R3 and R4? Like (R1 + R2)||(R3 + R4)?
 
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Because there is a continuous path around the resistors, they are shorted out and have no effect. So, the resistance is zero.
 
Ah I understand it now, not sure how I missed that. Thanks!
 
Uggh, I knew it couldn't be that easy! I drew a wire where there shouldn't have been one. This is the real circuit:

http://sogacity.com/images/circuit3.png

Anyways, I still have no idea how to approach this problem. Would it be (R1||R4)+(R2||R3) since R1 and R2 seem to be in series and R1R4 and R2R3 look to be in parallel?
 
Last edited by a moderator:
It looks like they touch at the centre point.

So, yes, the top two are in parallel and the bottom two are in parallel and then the two parallel parts are in series.

It might look more familiar like this:

[PLAIN]http://dl.dropbox.com/u/4222062/series%20parallel.PNG
 
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Awesome, thanks a lot.
 

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