Engineering Finding current in a RLC circuit using kirchhoff laws

AI Thread Summary
The discussion focuses on finding the current I1 in an RLC circuit using Kirchhoff's laws. The user expresses confusion over branches without resistance affecting their equations and attempts to apply Kirchhoff's first and second laws but struggles to derive a useful solution. Clarifications are made regarding the circuit's configuration, specifically that it is a DC circuit immediately after commutation, with the commutator switch closed in series with E2 and R1. Participants suggest replacing the inductor and capacitor with a short-circuit and open-circuit, respectively, for steady-state DC analysis. The user seeks further assistance with the equations to accurately calculate the currents during the capacitor charging phase.
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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