I finding the Thevenin equivalent resistance

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Discussion Overview

The discussion revolves around finding the Thevenin equivalent resistance across opened terminals in a circuit. Participants are exploring methods for circuit analysis, including identifying resistors in series and parallel, and applying Thevenin's theorem.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about identifying parallel resistors and redrawing the circuit after simplification.
  • Another participant requests to see the original poster's work to facilitate checking the answer.
  • A hint is provided suggesting the use of a voltage source at the output to analyze the circuit, indicating a method for determining Thevenin resistance through current analysis.
  • One participant questions the inclusion of a specific resistor and suggests visualizing the circuit from different angles to understand current paths better.
  • Another participant challenges the assumption that certain resistors are in parallel, prompting a review of the definitions of series and parallel configurations.
  • A different approach is proposed involving the calculation of open-circuit voltage (VOC) and short-circuit current (ISC) to find the Thevenin equivalent resistance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct approach to simplify the circuit or the identification of resistors in series and parallel. Multiple competing views and methods are presented.

Contextual Notes

Some participants express uncertainty about the circuit configuration and the definitions of series and parallel resistors, indicating potential limitations in their understanding of circuit analysis.

SpiralStars
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Homework Statement


https://imgur.com/a/XD3Km4t
upload_2018-5-23_22-52-42.png


I'm trying to find the thevenin equivalent resistance across the opened terminals.

Homework Equations



I know you short circuit the voltage source and do simple circuit analysis, however I'm getting confused in determining what resistors are parallel to each other and how to redraw the diagram once I simplified. How do I do this ?

The Attempt at a Solution


My attempt got me 426.0.26 ohmz.
 

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SpiralStars said:
My attempt got me 426.0.26 ohmz.
Please show us your work. It is much easier to check your answer if you show your work.
 
Hint: If there are no obvious resistances in parallel or in series that would allow you to reduce the circuit by simple methods then you should consider placing a voltage source at the "output" and solving for the current it would drive into the circuit; The problem then becomes one of general circuit analysis involving whatever methods you've learned. Once you know that current, then Ohm's law will tell you the resistance that the source sees.
 
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The pictures are blurry but there's a approach that I always use.Lets suppose you started from one of the open terminals, let's say upper one. Also I didnt understand why you included ##100Ω## resistor.

In any case try to follow a current path in your mind. If the path divides two and you can't reach the B in 1 path then they must be parallel.

Second approach is that try to look the circuit from the open ends side but not from the normal image. I mean move the image 90 degrees right and try to look it that way. Also I think this is a homework question
 
You seem to think that R3 and R4 are in parallel, yes? If so, you might want to go back to the basic definitions of what is series and what is parallel.
 
I personally like solving for VOC and ISC when simplifying the circuit is not super obvious; you can use Ohm's law with those terms to reveal the RTH.

VOC = Output voltage with output as open circuit
ISC = Current going along the output node when it is short circuited to its reference ground.
 

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