Calculating Potential and Voltages in Series Capacitors

In summary, the potential at point D for the given circuit is 15V, and the voltage across the 32 microFarad capacitor is 1.39V. This can be found using the conservation law of charge and calculating the overall capacitance of the three capacitors in series. Alternatively, voltage division can also be used by treating the capacitors as impedances.
  • #1
triplezero24
16
0
1. For http://www.pen.eiu.edu/~cuemc4/circuit.bmp picture.. Calculate the potential at point D.

2. I 15-V battery is connected to three capacitors in series. The capacitors have the following capacitances: 4.5microFarads, 12.0microFarads, and 32microFarads. Find the voltage across the 32microFarad capacitor.

I am so lost. :frown: :confused:
 
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  • #2
i can't see the circuit
 
  • #3
1. Can't load the circuit diagram.

2. The absolute value of the charge collected on each capacitor plate will be equal (conservation law of charge), suppose it is Q. The overall capacitance of the three capacitors in series is: (4.5^-1 + 12^-1 + 32^-1)^-1 uF = 2.97 uF (uF = microfarad)

Q = CV
= 2.97 * 10^-6 * 15 C
= 4.45 * 10^-5 C

So the voltage across the 32 uF capacitor is:
V = Q/C
= (4.45 * 10^-5) / (32 * 10^-6) V
= 1.39 V

NB: You could have also used voltage division by treating the capacitances as impedances with values -j/(2pi*fC) ohms, since the 15V DC source can be thought of as a sinusoidal voltage source with infinitesimal frequency.
 
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1. How do you calculate the total potential difference in a series circuit with capacitors?

To calculate the total potential difference in a series circuit with capacitors, you must add the individual potential differences of each capacitor. This can be done by using the formula Vt = V1 + V2 + V3 + ..., where Vt is the total potential difference and V1, V2, V3, etc. are the individual potential differences of each capacitor.

2. How do you calculate the equivalent capacitance in a series circuit?

The equivalent capacitance in a series circuit can be calculated by using the formula 1/Ct = 1/C1 + 1/C2 + 1/C3 + ..., where Ct is the equivalent capacitance and C1, C2, C3, etc. are the individual capacitances of each capacitor. Once you have the equivalent capacitance, you can use it to calculate the total charge in the circuit using the formula Q = Ct x Vt, where Q is the total charge and Vt is the total potential difference.

3. Can you calculate the potential difference across each capacitor in a series circuit?

Yes, you can calculate the potential difference across each capacitor in a series circuit by using the formula Vc = Qt/Cc, where Vc is the potential difference, Qt is the total charge in the circuit, and Cc is the capacitance of the specific capacitor you are calculating for.

4. What is the relationship between potential difference and capacitance in a series circuit?

In a series circuit with capacitors, the potential difference is directly proportional to the capacitance. This means that as the capacitance increases, the potential difference also increases, and vice versa. This relationship can be represented by the formula Vc = Qt/Cc, where Vc is the potential difference, Qt is the total charge, and Cc is the capacitance of the specific capacitor.

5. How does adding more capacitors in a series circuit affect the total potential difference?

Adding more capacitors in a series circuit increases the total potential difference. This is because the total potential difference is the sum of the individual potential differences of each capacitor. So, as more capacitors are added, the total potential difference also increases. However, the potential difference across each capacitor will remain the same in a series circuit.

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