Calculating Equivalent Voltage in a Complex Circuit: Thevenin vs. Norton

  • Thread starter Thread starter jisbon
  • Start date Start date
  • Tags Tags
    Voltage
Click For Summary

Homework Help Overview

The discussion revolves around calculating the equivalent voltage in a complex circuit using Thevenin and Norton transformations. Participants are exploring the implications of circuit transformations and the identification of equivalent resistance.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to transform current and voltage sources to simplify the circuit analysis. Questions arise about the correctness of transformations and the identification of points for equivalent resistance. There is also discussion on whether transforming voltage sources might be a better strategy.

Discussion Status

The discussion is active with participants questioning the validity of transformations and the setup of the circuit. Some guidance has been offered regarding the potential for source transformations, but there is no explicit consensus on the best approach yet.

Contextual Notes

Participants note constraints related to circuit layout and the clarity of the drawing, which may affect the understanding of where equivalent resistance should be calculated. There is also mention of an extra wire causing a short circuit, which adds complexity to the problem.

jisbon
Messages
475
Reaction score
30
Homework Statement
Use source transformation to reduce the circuit to a single voltage source Vs in series with a single resistor R. What are the values of Vs and R?
Relevant Equations
-
1597632087664.png

From this, I can transform the current source to:
1597632154939.png


I can then find the equivalent resistance to be (30//20)//40 = 9.23 ohms.
However, I am not sure how to find the equivalent voltage in this case?
What should I do to start?
 
Physics news on Phys.org
That's a wrong transformation. Read this https://people.clarkson.edu/~jsvoboda/eta/dcWorkout/sourceXfrm.pdf a bunch of examples.
 
archaic said:
That's a wrong transformation. Read this https://people.clarkson.edu/~jsvoboda/eta/dcWorkout/sourceXfrm.pdf a bunch of examples.
I don't seem to get it, isn't the transformation correct for the left side though?
 
jisbon said:
I don't seem to get it, isn't the transformation correct for the left side though?
1505994858.png

You have an extra wire that is making a short circuit.
And, by the way, wouldn't you think that transforming the voltage sources instead would be a better strategy?
 
archaic said:
View attachment 267867
You have an extra wire that is making a short circuit.
And, by the way, wouldn't you think that transforming the voltage sources instead would be a better strategy?
Ah ok I get what you mean, so something like:

1597653428920.png

How do I exactly find the 'total' voltage in this case tho?
 
jisbon said:
Ah ok I get what you mean, so something like:

View attachment 267868
How do I exactly find the 'total' voltage in this case tho?
You use the source transform to make the problem easier. non-ideal voltage sources in parallel are hard. Maybe you could transform the sources into something else?
 
jisbon said:
Ah ok I get what you mean, so something like:

View attachment 267868
How do I exactly find the 'total' voltage in this case tho?
That is correct, but follow my advice, don't do that transformation.
 
jisbon said:
I can then find the equivalent resistance to be (30//20)//40 = 9.23 ohms.
How do you know between which two points the equivalent resistance is asked? Ditto for "single voltage Vs".

I am not sure if I understood this problem correctly.
 
cnh1995 said:
How do you know between which two points the equivalent resistance is asked? Ditto for "single voltage Vs".

I am not sure if I understood this problem correctly.
The drawing does not make it explicit, but the fact that all of the top endpoints of the devices in the middle merge onto a single wire and that all of the bottom endpoints of the devices in the middle merge onto a single wire strongly suggests that those two wires are the two points between which equivalent resistance is desired.

[I had the same reaction at first]
 
  • #10
You would be better served to change the two thevenin sections to norton sections so the whole thing is a bunch of Nortons in parallel.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
3
Views
2K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
Replies
9
Views
1K
Replies
4
Views
2K