Finding Wraparound Voltage in Series and Parallel Circuits

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Discussion Overview

The discussion revolves around determining the voltage seen by the wraparound (WA) in a circuit involving resistors R1, R2, R3, and R4, as well as two voltage sources. Participants explore the configuration of these components, debating whether they are in series or parallel, and the implications for calculating voltage drops and currents in the circuit.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses uncertainty about the arrangement of resistors R3 and R4, suggesting they might be in series with R1 and R2.
  • Another participant proposes redrawing the circuit to clarify the relationships between components and identify parallel resistors.
  • A participant mentions using source transformations to simplify the circuit, leading to a new configuration with a reduced resistor.
  • There is a contention regarding the independence of the voltage sources, with one participant asserting that they do not affect each other despite sharing a ground connection.
  • One participant describes a method for calculating the current through resistors in parallel, while another questions their understanding of ground connections in the circuit.
  • Participants discuss the effect of the 28V source, with one noting it only affects R4 and questioning the validity of their previous calculations involving source transformations and voltage dividers.
  • Clarifications are made about the lack of a return path for current between the two voltage sources, impacting their interaction in the circuit.

Areas of Agreement / Disagreement

Participants express differing views on the configuration of the circuit, the interaction between voltage sources, and the correct methods for calculating voltages and currents. No consensus is reached on these points, and multiple competing interpretations remain.

Contextual Notes

Participants highlight potential misunderstandings regarding the concept of ground and its role in circuit analysis, as well as the implications of source transformations and voltage dividers. These discussions indicate that assumptions about circuit connections and configurations may vary among participants.

Who May Find This Useful

This discussion may be useful for individuals studying circuit analysis, particularly those interested in understanding the relationships between components in series and parallel configurations, as well as the implications of grounding in electrical circuits.

KrNx2Oh7
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I need to find the voltage seen by the wraparound (WA) after R1, but I'm not really sure what's in parallel or series.

I think R3 is in series with R4 which are in series with the r1 and r2? If that was the case its a standard circuit problem, but not sure.

http://imageshack.us/photo/my-images/219/59571528.png/

http://imageshack.us/f/219/59571528.png/
 
Last edited:
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If you redraw the circuit like this:

cct 18july.PNG


You can see the full picture.

The two voltage supplies are really grounded on their negative terminals and these ground points, and the others in the circuit, can be regarded as all joined together.

Can you see now which resistors are in parallel?
 
Redid it with source transformatiosn

and what I get is

my original 15V source connected to R1 connected to reduced resistor let's call it Ra and a changed voltage.
 
Last edited:
No, the voltage sources are independent of each other. They are not in series or parallel and they affect different resistors.

You follow the path from each power supply positive output back to its negative.

Even if they share a ground connection, this does not mean they share current.
 
step by step this is what I did.

28V/(R2+R4) is current source in parallel with (R2+R4)

reduce the resistors to R3||(R2+R4)

change it to voltage source of 28(R3||R2+R4)/(R2+R4) and the resistor is (R3||(R2+R4))

so its 15V connected to R1 connected to other resistor connected voltage source connected to ground right?

and my vout is sensed over that new calculated resistor
 
Also I'm thinking I'm not getting the concept of ground then

Aren't all grounds connected since they all are 0.
 
They are all connected but not because they are zero volts. The circuit would function just the same if the ground symbols were not there.

The only thing that matters is the path between the terminals of each voltage source.

For example, the 28 volt source in your problem only sends current through one resistor. Can you see which one?
 
I see that the 28V only affects R4.

For the Vout, just to verify it is the voltage across whatever the 28V R2 R3 R4 is reduced to correct?

Was the source transformation method I did plus voltage divider afterwards not correct?
 
What if I drew it like this:

cct 18july 2.PNG


Does that make it clearer?

I see that the 28V only affects R4.
That's right.

For the Vout, just to verify it is the voltage across whatever the 28V R2 R3 R4 is reduced to correct?

No, the 28 V supply has no effect on the output.

Was the source transformation method I did plus voltage divider afterwards not correct?
Yes, it was not correct.
 
  • #10
No current flows from the "15V circuit" to the "28V circuit" since there is no return path...so they do not affect each other like you said

So the Vout I'm looking for is the voltage drop of R3||R2 and the right side doesn't affect anything?

Also how did your first drawing with all the grounds show that there was no return path for the 28V right side circuit?
EDIT: I see it now the high side of the 28V connects to the low of R2 (ground symbol) and not highthanks for being patient with me btw
 

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