Kirchhoff's Law Violations: Transmission Line Equivalent Circuit

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Discussion Overview

The discussion revolves around the conditions under which Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL) may not hold true, particularly in the context of transmission lines. Participants explore the implications of transmission line length relative to wavelength and other factors that may lead to violations of these laws.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that KVL and KCL are valid only when the wavelength (λ) is much greater than the length (L) of the transmission line.
  • Others argue that KVL becomes invalid when time-varying magnetic fields create electric fields, while KCL may fail due to the divergence of current density (J) caused by charge dispersion in a conducting medium.
  • A participant suggests that KVL and KCL are only valid when the transmission line's length L is very small compared to the wavelength (λ), although this claim is later challenged.
  • Another participant corrects the previous assertion, stating that the wavelength must be much greater than the length of the wires to avoid transmission line effects or antenna effects.

Areas of Agreement / Disagreement

Participants express differing views on the conditions for the validity of KVL and KCL, indicating that multiple competing perspectives remain without a consensus on the precise circumstances under which these laws may fail.

Contextual Notes

Some claims depend on specific definitions of wavelength and length, and there are unresolved mathematical implications regarding the conditions for KVL and KCL violations.

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Discuss under what circumstances kirchhoffs voltage law and kirchhoffs cureent law are no longer valid, and give an equivalent circuit for the tranmission line in those circumstances?
 

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I have found out that kirchhoffs voltage law and krichoff's current law are only vaild when the wavelength (λ) << L.
are there any other circumstances??
 
Discuss under what circumstances kirchhoffs voltage law and kirchhoffs cureent law are no longer valid, and give an equivalent circuit for the tranmission line in those circumstances?

a) it is only valid when the transmission line's length L is very small comparing to the wavelength (λ) of the wave passing through the transmission line.
 
KVL is invalid when time varying magnetic filed creates Electric Field.
KCL is invalid when Divergence of J is created by dispersion of a ball of charge placed inside a conducting medium.
 
(Merged 2 threads...)
 
duniltmg1 said:
I have found out that kirchhoffs voltage law and krichoff's current law are only vaild when the wavelength (λ) << L.
are there any other circumstances??

If L is the length of the wire, then this is not correct.

wavelength (λ) >> L.
The wavelength is has to be much greater than the length of the wires or there may be transmission line effects or even antenna effects where power is radiated and lost from the circuit.
 

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