Help with intro circuit analysis problem Thevenin and max power prob

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Discussion Overview

The discussion revolves around an introductory circuit analysis problem involving Thevenin's theorem and maximum power transfer. Participants are analyzing mesh currents, voltage drops, and the relationships between various circuit elements, seeking clarification on their calculations and methodologies.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes their approach using source transformation and mesh analysis, leading to a set of equations involving mesh currents and voltage drops.
  • Another participant questions the correctness of the loop equations and the presence of a specific term in both equations, asking for clarification on the derivation.
  • There is a discussion about the role of Io as a fixed source and the implications for naming conventions of mesh currents.
  • Participants explore the relationship between Vx and the mesh currents, with one suggesting that Vx can be expressed in terms of i2.
  • There is a suggestion to find the Thevenin resistance using the open circuit voltage and short circuit current, with participants discussing the implications of dependent sources in the circuit.
  • Some participants express confusion about how to solve for mesh currents when certain variables are not numerical values.
  • There is a suggestion to leave the load resistor in the circuit to simplify finding both the Thevenin voltage and resistance.

Areas of Agreement / Disagreement

Participants express differing views on the correct approach to mesh analysis and the implications of using certain variable names. There is no consensus on the correctness of the initial equations or the best method for determining the Thevenin equivalent.

Contextual Notes

Participants note the presence of dependent sources and the need to consider their effects when simplifying the circuit. There is also mention of potential sign errors in voltage drop calculations.

  • #31
gneill said:
No, you'll get an expression for I3 in terms of RL and Io. That expression will allow you to pick out the Thevenin voltage and resistance. With the Thevenin resistance you known the value of RL that will maximize the power delivered to RL.

When we solve for i3 we will have two unknown variables in it right? Rl and Io
 
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  • #32
nchin said:
When we solve for i3 we will have two unknown variables in it right? Rl and Io

Yes. But we have the advantage of knowing something about RL and its relationship to Rth for maximum power transfer, regardless of the value of Io. As I stated previously, we can pick out Rth and Vth from the result of finding the expression for i3*RL.
 

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