Energy stored in a capacitor


by zorro
Tags: capacitor, energy, stored
zorro
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#1
Mar6-11, 05:41 PM
P: 1,395
1. The problem statement, all variables and given/known data



Long time after closing K1,k2 and k3 the energy stored in each capacitor is?


3. The attempt at a solution

My method is to find out an expression for the current through the capacitor (of net capacitance 2C) at any time t and use I = CdV/dt to find out V across it at t=inf.

However this method appears to be very long. Is there any shortcut?
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Antiphon
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#2
Mar6-11, 06:05 PM
P: 1,781
Yes. At T=inf the current through the capacitors is zero.
SammyS
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#3
Mar6-11, 06:28 PM
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Quote Quote by Antiphon View Post
Yes. At T=inf the current through the capacitors is zero.
Also notice: that will leave you with a fairly simple circuit. The capacitors in combination with R3 are in parallel with R[SUB]2[/SUB, but the voltage drop across R3 is zero since there is no current through it.

zorro
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#4
Mar7-11, 02:40 AM
P: 1,395

Energy stored in a capacitor


So you mean voltage drop across any capacitor is V ?
SammyS
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#5
Mar7-11, 07:51 PM
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Quote Quote by Abdul Quadeer View Post
So you mean voltage drop across any capacitor is V ?
No.

As t → ∞ :

The only current flowing is through R1 and R2.

What is the voltage drop across R2?
zorro
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#6
Mar8-11, 03:22 AM
P: 1,395
Its V/3
Thank you!!
SammyS
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#7
Mar8-11, 01:55 PM
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Quote Quote by Abdul Quadeer View Post
Its V/3
Thank you!!
Correct !


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