RLC Circuit DC Homework Solution

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The discussion focuses on solving a homework problem related to an RLC circuit and the behavior of currents at the moment the switch is closed. Participants clarify that at time t=0, both the current through the inductor and the charge on the capacitor are zero, which simplifies the equations needed to find the initial values of the currents. They emphasize that while the equations are important for later calculations, understanding the initial conditions is crucial for solving the problem. The conversation also touches on the behavior of the circuit as it reaches a steady state over time, confirming that the current through the capacitor will be zero once fully charged. Overall, the thread highlights the importance of applying fundamental circuit principles to analyze transient and steady-state conditions in RLC circuits.
  • #31
Arman777 said:
Well ##i_2=0## since capacitor is full.There can't be current.I couldn't find ##i_1##...I think its 1A but I am ot sure...I thought ##ε=i_1(R_1+R_3)+L(di_1/dt)##
After very long time, the circuit is in stationary state. Nothing changes, the time derivative of the currents. i 1=1 A and i2=0 are correct.
Arman777 said:
Part (e) I guess Q=εC
Part (f) If its one ampere and I find charge correctly then ##U_L=1/2Li^2## and ##U_C=Q^2/2C##
The capacitor is not connected directly to the battery, there are two resistors in between. Is some potential drop across those resistors?
 
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  • #32
ehild said:
The capacitor is not connected directly to the battery, there are two resistors in between. Is some potential drop across those resistors?
Oh you are right yes, then ##Q/C=ε-i_3R_3-i_2R_2## ##i_2=0## and ##i_3=1A## ?
 
  • #33
Arman777 said:
Oh you are right yes, then ##Q/C=ε-i_3R_3-i_2R_2## ##i_2=0## and ##i_3=1A## ?
Yes.
 
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Likes Arman777
  • #34
ehild said:
Yes.
Thanks a Lot.
 
  • #35
Well done!
 
  • #36
Second well done

upload_2017-5-22_17-59-25.png


was what I was fishing for in #21
 
  • #37

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