How Did They Derive the Equation Using Kirchhoff's Voltage Law?

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Discussion Overview

The discussion revolves around understanding the derivation of an equation using Kirchhoff's Voltage Law (KVL) in the context of a circuit analysis problem. Participants are exploring the application of KVL to a specific loop in a circuit involving resistors and an operational amplifier.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion about how the equation was derived from KVL and seeks clarification on the specific points of application.
  • Another participant clarifies that KVL should be applied to a loop rather than a point and specifies that the relevant loop includes resistors R4 and R3.
  • A suggestion is made to redraw the circuit diagram to better visualize the loop for mesh analysis, including proper modeling of the operational amplifier.
  • A hint is provided about the connection of ground symbols in the circuit, implying their importance in the analysis.
  • One participant shares a strategy for writing a KVL sum that equals zero, recommending a rearrangement of the equation without starting with "Vo = " and emphasizing the importance of considering the sign of voltages based on current direction.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the derivation process, as there are multiple approaches and suggestions being discussed. The discussion remains unresolved regarding the specific steps to derive the equation.

Contextual Notes

Participants have not fully articulated all assumptions or dependencies related to the circuit elements, and there may be unresolved mathematical steps in the derivation process.

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Homework Statement


I am following book and they got this equation but i don't know how they got it ??




Homework Equations






The Attempt at a Solution


I know they use kirchhoffs voltage law but at which point they are choosing and how they are going and acquire this equation.?
 
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You don't apply the voltage law at a point - you apply it to a loop.
They tell you which loop they applied it to - the one containing R4 and R3.

Redraw the circuit diagram so the loop containing R4 and R3 looks like a loop and do the mesh analysis - don't forget to appropriately model the op-amp.
 
Hint: Remember that all ground symbols are connected to each other.
 
I find it helps by writing a KVL sum so it adds to zero. Then rearrage it. Don't start by writing "Vo = "

eg start with an equation of the form...

(v1) + (v2) + (v3)... = 0

Remembering that v1,v2, or v3... might be negative depending on which direction is defined as positive current.
 

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