Circuit/capicator/resistor problem

  • Thread starter physics213
  • Start date
In summary, the conversation discusses a circuit with a fully charged capacitor and three resistors. The first part of the question asks for the steady-state current in each resistor, which can be solved by treating the capacitor's branch as an open circuit. The second part asks for the charge on the capacitor, which can be found using the equation Q=CV after determining the correct voltage across the capacitor.
  • #1
physics213
20
0

Homework Statement



IMAGE ATTACHED!

In the figure below, suppose that the switch has been closed for a length of time sufficiently long enough for the capacitor to become fully charged. (R = 11.0 k, R2 = 15.0 k, R3 = 3.00 k, ΔV = 9.30 V)

Find the steady-state current in each resistor.

Find the charge on the capacitor.


Homework Equations



V=IR
Series/Parallel resistor equations.
C=Q/V

The Attempt at a Solution



I believe you have to use the loop rule but I can't figure out how to simplify the circuit, or even what to do after that. Please help!
 

Attachments

  • P[HYSICS.gif
    P[HYSICS.gif
    4.9 KB · Views: 680
Physics news on Phys.org
  • #2
When the capacitor is fully charged, current stops flowing into it, so you can treat its branch as an open circuit. See if that gives you a hint about the next step. How does that affect the resistor that's in series with it? What simplifictions will then become possible?
 
  • #3
So the current in the resistor that is in series with the capacitor would be zero. Which would mean that the current in the other two resistors should be equal to each other, correct? Which would also mean the other two resistors are in series if I'm not mistaken.
 
  • #4
ok I got the correct answer for the current through the resistors problem! Thanks a lot.
 
  • #5
Wouldn't the second part of this question (What is the charge on the capacitor?) just be Q=CV? I can't get the correct answer from that though...
 
  • #6
Correct, R and R2 will be in series after the current in the R3 branch decays to zero. After R3 has no current, next step, what is the voltage across R3? Using that fact, how does the voltage across the capacitor compare to the voltage across R2: would it be smaller or greater or equal? Finally, will the full voltage source V be applied across R, or will the full voltage source be applied across R2, or will V be divided somehow between R and R2? You have to get the capacitor voltage right before you can apply Q=CV.
 
Last edited:

FAQ: Circuit/capicator/resistor problem

1. What is a circuit?

A circuit is a complete path through which electricity can flow. It includes a power source, conductors, and a load or device that uses the electricity.

2. What is a capacitor?

A capacitor is a passive electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulator, with the ability to store and release charge.

3. What is a resistor?

A resistor is a passive electronic component that resists the flow of electrical current. It is used to control the amount of current or voltage in a circuit and is often used to control the brightness of lights or the speed of motors.

4. How do I calculate the total resistance in a circuit?

To calculate the total resistance in a circuit, you need to add up the individual resistances in series or use the formula for resistors in parallel. In series, the total resistance is equal to the sum of all the individual resistances. In parallel, the total resistance is calculated by dividing the product of all the resistances by the sum of the resistances.

5. How does a capacitor affect the flow of electricity in a circuit?

A capacitor can store and release charge, which can affect the flow of electricity in a circuit. When the capacitor is fully charged, it acts as an open circuit, blocking the flow of current. When the capacitor discharges, it acts as a short circuit, allowing current to flow through. This can be useful in smoothing out voltage spikes or creating time delays in a circuit.

Similar threads

Back
Top