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

In summary, the conversation is about finding the value of U on R2 after a long time of the switch being closed. The capacitors are charged so there is no current going through. Kirchof's rule is used to calculate U and the final equation is U=R2/(R3+R2+(R1R/R1+R))*Uo. The person is asking if this is correct and if someone can provide an example and explanation. It is mentioned that if there is no current passing through a component, it can be removed from the circuit without affecting anything. The conversation ends with a question about why there is current flowing through R1.
  • #1
nisamto
2
0
Thread moved from Electrical Engineering forum, so no template included.
https://qph.is.quoracdn.net/main-qimg-c22d8aa4be4fc2ed9b2f1c7060982e04?convert_to_webp=true
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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  • #2
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?
 
  • #3
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 throught R1?
 
  • #4
nisamto said:
No. How come that there is current throught 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
 
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  • #5
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.
 

1. How do you calculate the value of U on R2 long time after the switch is closed?

The value of U on R2 long time after the switch is closed can be calculated using the formula U = I x R2, where I is the current flowing through R2 and R2 is the resistance of the circuit. This formula is derived from Ohm's Law, which states that the voltage (U) across a resistor is equal to the product of the current (I) and the resistance (R).

2. What factors affect the value of U on R2 long time after the switch is closed?

The value of U on R2 long time after the switch is closed can be affected by several factors such as the initial voltage across R2, the resistance of R2, the duration of time since the switch was closed, and the type of circuit. These factors can impact the flow of current and therefore, the value of U on R2.

3. Is the value of U on R2 constant long time after the switch is closed?

No, the value of U on R2 is not constant long time after the switch is closed. It may decrease or increase depending on the factors mentioned above. However, it will eventually reach a steady state where the value of U on R2 remains constant.

4. How does the value of U on R2 change over time after the switch is closed?

The value of U on R2 changes over time after the switch is closed due to the process of charging or discharging of the capacitor in the circuit. Initially, the value of U on R2 may be high, but it will decrease as the capacitor gets charged. Once the capacitor is fully charged, the value of U on R2 will remain constant until the switch is opened again.

5. Can the value of U on R2 be negative long time after the switch is closed?

Yes, the value of U on R2 can be negative long time after the switch is closed if the capacitor in the circuit is discharged through R2. This can happen if the initial voltage across R2 is greater than the voltage of the power source. In this case, the current will flow in the opposite direction, resulting in a negative value of U on R2.

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