Find the charge of Capacitor 2 in the circuit

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Homework Help Overview

The discussion revolves around finding the charge of Capacitor 2 (C2) in a circuit using Kirchhoff's method. The original poster has already determined the overall current and the charge on Capacitor 1 (C1) but is encountering difficulties with the subcircuit containing C2.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore the known potential differences in the subcircuit and question how to write Kirchhoff's equation for C2. There is discussion about the implications of a fully charged capacitor on the voltage across resistors and the overall circuit behavior.

Discussion Status

Participants are actively engaging with the problem, clarifying known values and potential differences. There is a focus on understanding the behavior of the circuit components, particularly regarding the effects of a fully charged capacitor on voltage contributions.

Contextual Notes

All resistances, voltages, and capacitances are known, but there is a need for clarification on the potential differences across the resistors in the subcircuit. The original poster has provided a circuit diagram, but further annotation is requested to highlight known values.

Tomi Kolawole
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Homework Statement


media%2F208%2F208d83af-d0cc-41dd-9adf-fd2111268b66%2FphpXJOsJE.png


Homework Equations


I am to use korchkoffs method to solve this problem

The Attempt at a Solution


I already solved for the overall current which is the same throughout because C1 and C2 impeded current flow in sections of the circuit and i have found the charge on c1 BUT I HAVE ISSues evluating the bottom right mini-circuit containing C2 to find its charge Q2.I don't know how write its korchoff equation
 

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What potential differences do you already know in that subcircuit?
 
all the Resistances Voltages and Capacitance are known
 
Tomi Kolawole said:
all the Resistances Voltages and Capacitance are known
And what are they? Can you annotate a drawing of the subcircuit with the known values of potential differences?
 
The values of the known circuit components are at the very bottom of the image.its easy to miss aha.

This is my Circuit diagram with the current direction and teminals laballed
uy9xXGv.png
 

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Can you pencil in the known potential difference values on that diagram?
 
ryPpiy4.png
V1 is not in this subcircuit that i made but you can see it in the overall diagram in the original image
 

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Okay, let me clarify my request. What are the potential differences across the resistors in the subcircuit?
 
Its V=IR so V=4/3 * 3 so the resistors have a V of 4 Volts
My Calculated I(current)= 4/3 and R is a given value of 3.
The capacitor is fully charged since the current (as stated in the question) has been flowing for awhile.SO i'M BASically wondering if the v2 AND R on the same branch as the capacitor (C2) will still contribute voltage even if there is no current flowing through their branch cause of the Fully charged Capacitor C2
 
Last edited:
  • #10
Tomi Kolawole said:
Its V=IR so V=4/3 * 3 so the resistors have a V of 4 Volts
My Calculated I(current)= 4/3 and R is a given value of 3.
Okay.
The capacitor is fully charged since the current (as stated in the question) has been flowing for awhile.SO i'M BASically wondering if the v2 AND R on the same branch as the capacitor (C2) will still contribute voltage even if there is no current flowing through their branch cause of the Fully charged Capacitor C2
Sure, voltage source always has a fixed potential difference. What's the potential difference across a resistor with zero current flowing?
 
  • #11
0 FOR THE RESISTOR since i is 0 but the battery itself still has a voltage? right?
 
  • #12
Tomi Kolawole said:
0 FOR THE RESISTOR since i is 0 but the battery itself still has a voltage? right?
Right. So you should be able to write KVL for the loop with the only unknown potential difference being that of the capacitor.

upload_2018-3-20_11-33-20.png
 

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  • #13
Tomi Kolawole said:
0 FOR THE RESISTOR since i is 0 but the battery itself still has a voltage? right?
Yes.

Since you've correctly said that the current through the capacitors is zero, just remove them from the circuit and keep the respective terminals open. How does the current flow in this new circuit?
 
  • #14
thank you so much kind sir!
 

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