Charge on a capacitor in a series

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SUMMARY

The discussion focuses on calculating the charge on capacitor C5 in a series circuit containing five capacitors with specified values: C1 = C5 = 3.9 μF, C2 = 3.9 μF, C3 = 5.7 μF, and C4 = 4.2 μF, powered by a 12 V battery. It is established that the charge on capacitors in series is the same, while the voltage across each capacitor varies based on their capacitance values. The confusion arises from the incorrect assumption that the voltage is equally divided among the capacitors. The correct approach involves calculating the equivalent capacitance of the series configuration.

PREREQUISITES
  • Understanding of capacitor configurations (series and parallel)
  • Knowledge of the formula C=Q/V for capacitors
  • Ability to calculate equivalent capacitance for series circuits
  • Familiarity with basic circuit analysis principles
NEXT STEPS
  • Calculate the equivalent capacitance of capacitors C2, C3, and C4 in series
  • Learn how to derive charge on capacitors in series using the formula Q = C_total * V
  • Explore the impact of varying capacitance values on voltage distribution in series circuits
  • Study practical applications of capacitors in electronic circuits
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Students studying electrical engineering, physics enthusiasts, and anyone seeking to understand capacitor behavior in series circuits.

acdurbin953
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Homework Statement



103szyq.png

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A circuit is constructed with five capacitors and a battery as shown. The values for the capacitors are: C1 = C5 = 3.9 μF, C2 = 3.9 μF, C3 = 5.7 μF, and C4 = 4.2 μF. The battery voltage is V = 12 V.

What is Q5, the charge on capacitor C5?

Homework Equations


C=Q/V

The Attempt at a Solution


Okay, I thought that voltage across series capacitors was all the same across each one. Treating the parallel system as one capacitor of equivalent capacitance, I thought you could just divide the voltage by 3, and then multiply by C5 to get the charge on C5. I tried this and the answer is wrong. I'm really confused.
 
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acdurbin953 said:

Homework Statement



103szyq.png

[/B]
A circuit is constructed with five capacitors and a battery as shown. The values for the capacitors are: C1 = C5 = 3.9 μF, C2 = 3.9 μF, C3 = 5.7 μF, and C4 = 4.2 μF. The battery voltage is V = 12 V.

What is Q5, the charge on capacitor C5?

Homework Equations


C=Q/V

The Attempt at a Solution


Okay, I thought that voltage across series capacitors was all the same across each one. Treating the parallel system as one capacitor of equivalent capacitance, I thought you could just divide the voltage by 3, and then multiply by C5 to get the charge on C5. I tried this and the answer is wrong. I'm really confused.

The voltage across capacitors in series is not the same, unless the capacitances are equal. What is the resultant of C2, C3 and C4? Is it equal to 3.9 μF?
I think you mix charge with voltage. The charge is same on series capacitors .
 

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