Effective resistance for Thevenin's theorem

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SUMMARY

The discussion focuses on calculating effective Thevenin's resistance in electrical circuits. The user initially calculated the resistance using the formula "Rt = R2 + R3 + R4," which is correct in certain contexts. However, the confusion arises from the inclusion of a "hanging edge" in the resistance measurement, which is crucial for accurately determining the effective resistance between two points. The effective resistance is defined as the resistance measured by an Ohmmeter placed across those points.

PREREQUISITES
  • Understanding of Thevenin's theorem
  • Basic circuit analysis techniques
  • Familiarity with resistance measurement using an Ohmmeter
  • Knowledge of series and parallel resistor combinations
NEXT STEPS
  • Study Thevenin's theorem applications in complex circuits
  • Learn about series and parallel resistor combinations in detail
  • Explore practical examples of measuring resistance with an Ohmmeter
  • Review circuit simulation tools like LTspice for visualizing Thevenin equivalents
USEFUL FOR

Electrical engineering students, circuit designers, and anyone involved in circuit analysis and Thevenin's theorem applications will benefit from this discussion.

irrationally
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Homework Statement


Me again. I again got confused with 2 similar things done differently on two different places. Let's say we have some arbitrary circuit and we want to replace a part of it with thevenin's generator. We also need to calculate effective Thevenin's resistance, which is where i found the problem.
New_Project.png

Suppose we need to find the effective resistance between points 1 and 2 at the picture. First of all , what does "effective resistance between two points" even mean. Second, I would say "Rt = R2+R3+R4" and according to my workbook that is correct. But if we take a look at this example (at 3:50 for example), we will see that the "hanging" edge is also taken into account. Why ?

Homework Equations


Thevenin's theorem

The Attempt at a Solution


Like i mentioned, I simply used "Rt = R2+R3+R4" which turns out to be correct. Why does the guy in the video take that other edge into account??[/B]
 
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The effective resistance between two points means, if you were to put an Ohmmeter across those points, that's the resistance that it would measure.

I didn't watch the video, but it would appear from the still shot that the "hanging edge" you refer to is in the path of the imaginary Ohmmeter that you would use to measure the effective resistance you're looking for.
 
Oh. well thanks, I feel like an idiot now :D
 
irrationally said:
Oh. well thanks, I feel like an idiot now :D
:) Don't. Better to ask and banish all doubt than to leave it to muddy your thought processes forever!
 

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