Capacitor Discharge: Physical Argument in Parallel & Series Connection

In summary: The summary is: "In summary, wiring two capacitors in parallel results in a larger overall capacitance, while wiring them in series results in a smaller capacitance due to eliminating half of the plate area. This affects the rate of discharge, with parallel capacitors discharging faster and series capacitors discharging slower."
  • #1
UrbanXrisis
1,196
1
I know that in a parallel connection, two capacitors that are charged and connected across a resistor, the switch is open, the capacitors discharge the same as if there was only one by itself? I need a physical argument as why this is? Any suggestions?

I know that in a series connection, two capacitors that are charged and connected across a resistor, the switch is open, the capacitors discharge slower than if there was only one by itself? I need a physical argument as why this is too? Any suggestions?
 
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  • #2
I'm not sure what "discharge the same" means exactly, but it doesn't sound correct.

A capacitor is basically just two metal plates separated by a small distance. Two capacitors wired in parallel are equivalent to one larger capacitor with the combined plate area of the two smaller capacitors. If you have two 1 F capacitors, wiring them in parallel results in a 2 F capacitor. A 1 F capacitor can discharge 1 ampere for 1 second per volt of charge. A 2 F capacitor doubles this to 2 amperes for 1 second per volt of charge. That doesn't sound like "the same" to me.

Two capacitors wired in series, however, results in a smaller capacitance. Why? Because by connecting the positive plate of one to the negative plate on the other, you're forcing both plates to have the same potential. (Every point in a conductor has the same potential.) Wiring them in series essentially eliminates half the plate area, and half the capacitance. If you halve the capacitance, you halve the time to discharge.

- Warren
 
  • #3


In a parallel connection, the two capacitors are essentially connected side by side, with the same voltage applied to each one. This means that the electric field between the plates of each capacitor is the same, and thus the amount of charge stored on each capacitor is also the same. When the switch is opened, the charges on both capacitors will flow through the resistor, resulting in a discharge that is equivalent to one capacitor discharging alone.

On the other hand, in a series connection, the two capacitors are connected in a chain, with the same current flowing through both. This means that the charge on each capacitor is dependent on the capacitance of the individual capacitor and the voltage applied to the entire circuit. As a result, the charge on each capacitor may not be equal and the discharge will be slower compared to a single capacitor. Additionally, the electric field between the plates of each capacitor will also not be the same, further affecting the discharge rate.

In conclusion, the physical argument for the difference in discharge rates in parallel and series connections lies in the distribution of charge and electric field within the capacitors. In parallel, the capacitors have the same charge and electric field, resulting in a faster discharge. In series, the charge and electric field may not be equal, leading to a slower discharge.
 

1. What is capacitor discharge and how does it work?

Capacitor discharge is the process by which a capacitor releases its stored electrical energy. This happens when the capacitor is connected to a circuit that allows the current to flow through it. As the current flows, the capacitor discharges its stored energy, causing a decrease in voltage across the capacitor.

2. What is the difference between parallel and series connection in capacitor discharge?

In parallel connection, capacitors are connected side by side with each other, while in series connection, capacitors are connected end to end. In parallel connection, the total capacitance increases while the voltage across each capacitor remains the same. In series connection, the total capacitance decreases while the voltage across each capacitor increases.

3. Does the physical arrangement of capacitors affect the discharge process?

Yes, the physical arrangement of capacitors can affect the discharge process. In parallel connection, the capacitors share the same voltage, and the total capacitance is the sum of the individual capacitances. In series connection, the capacitors have the same charge, and the total capacitance is the inverse of the sum of the inverses of individual capacitances.

4. How does the discharge time differ between parallel and series connection?

The discharge time in parallel connection is shorter compared to series connection. This is because in parallel connection, the total capacitance is higher, resulting in a larger amount of stored energy that needs to be discharged. In series connection, the total capacitance is lower, so the amount of stored energy that needs to be discharged is also lower, resulting in a longer discharge time.

5. Can capacitors in parallel or series connection discharge at the same time?

No, capacitors in parallel or series connection do not discharge at the same time. In parallel connection, the capacitors share the same voltage, so they discharge simultaneously. In series connection, the capacitors have the same charge, so they discharge in sequence, one after the other.

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