Finding current in a RLC circuit using kirchhoff laws

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Discussion Overview

The discussion revolves around finding the current flowing through a specific component (E1) in an RLC circuit using Kirchhoff's laws. Participants are addressing the complexities of circuit analysis, particularly in the context of a DC circuit immediately after commutation.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • The original poster expresses confusion regarding branches without resistance in their circuit equations.
  • Some participants inquire whether the analysis is for steady-state DC or AC, suggesting that for DC, inductors and capacitors can be simplified to short-circuits and open-circuits, respectively.
  • The original poster clarifies that the circuit is a DC circuit right after commutation, indicating a need to calculate currents while the capacitor is charging.
  • There is a correction regarding the identification of components, where E1 is mistakenly referred to instead of E2.
  • One participant seeks confirmation of the circuit's configuration, indicating a collaborative effort to clarify the setup.

Areas of Agreement / Disagreement

Participants are working towards understanding the circuit configuration and the nature of the analysis, but there is no consensus on the specific equations or methods to apply, and some confusion remains regarding component connections.

Contextual Notes

There are unresolved issues regarding the circuit's configuration and the assumptions made about the components' behavior immediately after commutation. The original poster's equations may be incomplete or incorrect, but this has not been definitively established.

karlis123
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Homework Statement



Find current flowing through E1 ( find I1).

Homework Equations



I see 6 currents, atleast until the capacitor is charged, what i find confusing are the branches without any resistance and they seem to mess up my equations.

The Attempt at a Solution


1st kirchhoff's law
I1+I5=I2
I3+I6=I1
I6+I5=I4
2nd kirchhoff's law
I2*L-I3*C=E1
I2*L+R1*I5=E2
I3*C+I6*R2=0

In the end i get 2*I5-I6=5 which doesn't solve anything for me so I guess I'm still missing something there.
Its been some time since I've done circuit calculations any help would be apritiated
 

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Are you after a steady-state DC analysis, or is this AC?

If DC, then the inductor and capacitor can be replaced by a short-circuit and an open-circuit, resp.
 
NascentOxygen said:
Are you after a steady-state DC analysis, or is this AC?

If DC, then the inductor and capacitor can be replaced by a short-circuit and an open-circuit, resp.

its a dc circuit right after commutation, the commutator switch is closed and is in series with E2 and R1 (i replaced it with a black line in the picture).
Here i found an example, as i understand i have to calculate the currents in the exact moment when the condenser is being charged.
any help with the equations would help allot.
Thanks in advance
 

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Last edited:
karlis123 said:
its a dc circuit right after commutation, the commutator switch is closed and is in series with E1 and R1 (i replaced it with a black line in the picture).

:confused: E1 and R1 don't appear to be connected in your circuit. So where is this commutator?
 
gneill said:
:confused: E1 and R1 don't appear to be connected in your circuit. So where is this commutator?

ow my bad! E2 I ment
 
So to be clear, the circuit looks like this?
attachment.php?attachmentid=46075&stc=1&d=1334077359.gif
 

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exactly
 

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