How I find value of U on R2 long time after switch is closed

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SUMMARY

The discussion focuses on calculating the voltage (U) across resistor R2 in an electrical circuit long after a switch is closed. The user applies Kirchhoff's voltage law and derives the equation U = R2/(R3 + R2 + (R1R/R1 + R)) * Uo, questioning its correctness. Participants clarify that once capacitors are fully charged, no current flows through them, and current continues to flow through resistors R1 and R2. The importance of redrawing the circuit to simplify analysis is emphasized.

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nisamto
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Thread moved from Electrical Engineering forum, so no template included.
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How to find value of U on R2 long time after switch is being closed?

Capacitors are charged so there is no current going through? Or?
I used kirchof rule so i get
Uo+Uc1-U=0
U=Uc1+Uo
U=R2/(R3+R2+(R1R/R1+R))*Uo

Is this correct or?

If not can someone do this example and explain me :)
 
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Is this homework? If so, I should be posted on the homework forum.

According to your diagram, if no current is passing through the capacitors, then current flows only through R2 and R1. Can you do the rest?
 
anorlunda said:
Is this homework? If so, I should be posted on the homework forum.

According to your diagram, if no current is passing through the capacitors, then current flows only through R2 and R1. Can you do the rest?
No. How come that there is current through R1?
 
nisamto said:
No. How come that there is current through R1?
Because with the switch closed there continues to be a current path through R1 even after the capacitors have charged.

http://www.imageshack.com/a/img109/4666/holly1756.gif
 
Last edited by a moderator:
Hint: If there is no current flowing through a component it can be removed from the circuit without affecting anything. Try redrawing your circuit with any such components replaced with an open circuit.

Edit: Actually this is not always true but try it anyway.
 

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