Thevenin Equivalent issue - I think I'm missing something

In summary, Thevenin equivalent circuit can be found by using the equation Vth= (R1/Rtotal)xVtotal, where R1 is the equivalent resistance of the circuit and Vtotal is the voltage across the circuit. In this case, the lecturer's solution for the Thevenin voltage is 2v, while the student's calculation resulted in 4.3v. The discrepancy could be due to the fact that the lecturer's solution considers the voltage across the output with no load, resulting in a simple voltage divider with 20kΩ and 5kΩ resistors.
  • #1
Cazicami
9
0

Homework Statement



Given the circuit (Attached in image) Find the thevenin equivalent circuit.

I know its a fairly simple thing, But I am not understanding where the lecturer is getting this answer from, unfortunately his solutions just state the voltage so I feel like I must be missing something important.



Homework Equations


Vth= (R1/Rtotal)xVtotal


The Attempt at a Solution



I tried finding the voltage dropped over the 10Ω + 5Ω resistors, which I found to be 4.3v

Vth= (R1/Rtotal)xVtotal = 4.3v
Where R1 = 10Ω+5Ω
Rtotal=35Ω

But the lecturers solutions simply say Vth=2v

Any help is appreciated
 

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  • #2
Cazicami said:

Homework Statement



Given the circuit (Attached in image) Find the thevenin equivalent circuit.

I know its a fairly simple thing, But I am not understanding where the lecturer is getting this answer from, unfortunately his solutions just state the voltage so I feel like I must be missing something important.

Homework Equations


Vth= (R1/Rtotal)xVtotal

The Attempt at a Solution



I tried finding the voltage dropped over the 10Ω + 5Ω resistors, which I found to be 4.3v

Vth= (R1/Rtotal)xVtotal = 4.3v
Where R1 = 10Ω+5Ω
Rtotal=35Ω

But the lecturers solutions simply say Vth=2v

Any help is appreciated
attachment.php?attachmentid=58536&d=1367869258.jpg


What's the voltage across the output if there's no load? I.e., there is no current drop across the 10 kΩ resistor. You have a simple voltage divider with 20kΩ and 5kΩ .
 

What is Thevenin Equivalent issue?

Thevenin Equivalent issue is a concept in circuit analysis that involves simplifying a complex circuit into a single equivalent circuit. This equivalent circuit has the same voltage and current characteristics as the original circuit at a particular load.

Why is Thevenin Equivalent important?

Thevenin Equivalent is important because it simplifies complex circuits, making them easier to analyze and understand. It also allows us to determine the maximum power that can be delivered to a load, making it useful for designing and optimizing circuits.

How do you find the Thevenin Equivalent of a circuit?

To find the Thevenin Equivalent of a circuit, you need to follow these steps:

  1. Remove the load resistor from the circuit.
  2. Calculate the open-circuit voltage (Voc) by using any appropriate method, such as voltage division.
  3. Calculate the short-circuit current (Isc) by replacing the load resistor with a short circuit and using any appropriate method, such as current division.
  4. The Thevenin Equivalent voltage (Vth) is equal to Voc, and the Thevenin Equivalent resistance (Rth) is equal to Voc/Isc.

What are the limitations of Thevenin Equivalent?

Thevenin Equivalent is only applicable to linear circuits, meaning that the voltage-current relationship must follow Ohm's law. It also assumes that the circuit is in steady-state and that there are no nonlinear elements present. Additionally, it is only accurate for a specific load and may not accurately represent the circuit's behavior at other loads.

How can I check if my Thevenin Equivalent is correct?

You can check the accuracy of your Thevenin Equivalent by replacing the load resistor with different values and comparing the results to the original circuit. The Thevenin Equivalent should provide the same voltage and current values for the same load resistance. You can also use simulation software to compare the behavior of the original circuit and the Thevenin Equivalent circuit.

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