RCC circuit

  • #1
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Homework Statement


The switch is closed at the moment t=0 and initial capacitor voltages are V01 and V02. How to find capacitor voltage time dependencies for both capacitors.

Homework Equations




The Attempt at a Solution


bezymjannyj-png.87168.png
bezymjannyj2-png.87170.png
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Answers and Replies

  • #2
501
66
What have you tried till now ?
 
  • #3
What have you tried till now ?
 

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  • #4
It seems fine .
I also think so, but my teacher's feedback:
"Time constant and steady-state are OK but the whole solution not - when I substitute t=0 and I don't get V1(0) and V2(0).

Steady-state may be found using charge conservation law. The difference between initial condition and steady-state decays exponentially in the 1st order circuit.

So please make another (final) iteration."
 
  • #5
501
66
I think I see a mistake - you first use indefinite integration for ' i ' as a function of ' t ' .
You don't use the limits correctly , i.e. , you don't subtract ' i ' at t = 0 .

Correct this , and then we can check if some other error creeps up .

Hope this helps .
 
  • #6
I think I see a mistake - you first use indefinite integration for ' i ' as a function of ' t ' .
You don't use the limits correctly , i.e. , you don't subtract ' i ' at t = 0 .

Correct this , and then we can check if some other error creeps up .

Hope this helps .
I did not quiet get it. What limits should I use: t and 0?
 
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  • #7
I did not quiet get it. What limits should I use: t and 0?
Could you explain what my teacher wanted to say by: "the whole solution not - when I substitute t=0 and I don't get V1(0) and V2(0)" and "difference between initial condition and steady-state decays exponentially in the 1st order circuit"
 
  • #8
501
66
Could you explain what my teacher wanted to say by: "the whole solution not - when I substitute t=0 and I don't get V1(0) and V2(0)" and "difference between initial condition and steady-state decays exponentially in the 1st order circuit"
The first part - At t = 0 , by your solution , V1 is not equal to V10 , as given in the question . Same for the other capacitor's initial potential drop ( V20 ) .

The second part - This means that q ( charge on any one capacitor at time t ) would be such a function that -

q0 - q = k.ek1 , where k and k1 are some constants that will be found on solving entirely .
 
  • #9
I think I see a mistake - you first use indefinite integration for ' i ' as a function of ' t ' .
You don't use the limits correctly , i.e. , you don't subtract ' i ' at t = 0 .

Correct this , and then we can check if some other error creeps up .

Hope this helps .
Isn't there when t=0: V1(0)=V10? Because by calculation I get the same equation.

Did you mean this? But answer doesn't change.
 
  • #10
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@@[email protected], please stop deleting the content of your posts. When other people have responded, deleting your posts makes it impossible to follow the discussion.
 

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