Solving circuit with Thevenin's theorem

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Discussion Overview

The discussion revolves around solving a circuit using Thevenin's theorem, specifically focusing on calculating the voltage and current across resistor R4. Participants share their approaches to determining the Thevenin equivalent voltage (Vth) and resistance (Rth) based on given circuit values.

Discussion Character

  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant states that they have determined Vth by observing that the voltage on R3 is equal to the voltage on R4.
  • The same participant notes that the current through R4 can be calculated using the formula IR4 = Vth / (Rth + R4), but expresses concern about needing an unrealistically low Rth value to match simulation results.
  • Several participants inquire about the procedure for finding Rth and Vth, indicating a need for clarification on the steps involved.
  • Another participant suggests looking at older threads for additional insights or help related to Thevenin's theorem.

Areas of Agreement / Disagreement

There is no consensus on the procedure for finding Rth and Vth, as multiple participants seek clarification and express uncertainty about the calculations involved.

Contextual Notes

Participants have not provided specific details on the assumptions or definitions used in their calculations, and there are unresolved questions regarding the values of Rth and Vth based on the circuit configuration.

Simonkaa
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Member advised to use the homework template for posts in the homework sections of PF.
Hey guys, I am supposed to solve for voltage and current on R4 using Thevenin's theorem here. Values are following:
U = 100V
R1 = 310
R2 = 610
R3 = 220
R4 = 570
R5 = 200

upload_2016-12-21_23-10-52.png

Now, I know I need to solve for Rth and Vth, so I put the circuit into simulation and figured out voltage on R3 is equal to voltage on R4, therefore that's my Vth. Although the theorem for current on R4 is
IR4 = Vth / (Rth + R4)
The simulation also showed current on R4 as 0.03 and pretty much my Rth would need to be as low as 12 to be suitable for this equation, which isn't possible given the current values for all resistors. Can anyone point me to the right direction? Thanks.
 
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What have you learned about finding Thevenin equivalents? What is the procedure?
 
gneill said:
What have you learned about finding Thevenin equivalents? What is the procedure?
That I need to find Rth and Vth first in order to calculate current and voltage on certain resistor
 
Simonkaa said:
That I need to find Rth and Vth first in order to calculate current and voltage on certain resistor
Okay, but what is the procedure for finding Rth and Vth for a circuit?
 
Simonkaa said:
That I need to find Rth and Vth first in order to calculate current and voltage on certain resistor
If you scroll down to the very foot of threads in these forums you will see links to older threads related to the current topic. Sometimes you will find help in posts in these earlier threads, but no promises.

https://www.physicsforums.com/attachments/holly-1756-gif.110502/
 

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