Why do capacitors in parallel and series discharge at different rates?

[UrbanXrisis]

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?

 

[chroot]

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

 

[M98Ranger]

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.