charging and discharging a capacitor?

Question

why does current start at a maximum and approach zero when discharging, why would the current flow in opposite directions?

Answer 1

You asked two questions.

Current starts at a maximum and approaches zero...
When a capacitor discharges through some resistance, the current decreases as the voltage decreases. Since the capacitor is discharging, the charge is being removed from the capacitor. The voltage decreases. As the voltage decreases, the current decreases. Once the voltage goes to zero, the current goes to zero, as the capacitor completely discharges.

The current reverses, flows in opposite directions...
If a voltage is applied to the capacitor, that is greater than the voltage stored in the capacitor, the voltage reverses and the capacitor starts charging to the higher voltage.

Answer 2

You can think of a capacitor as a mini battery.
The "mini" battery holds it's charge in an electrostatic field, instead of in some chemical reaction.

When you connect a capacitor to a battery, It's like charging a dead battery.

Think of it this way...
If you connect two batteries together then the dead battery gets charged up.
If the good battery moved ALL of its charge into the dead battery, the dead battery would be fully charged and become the good battery.
Conversly, the good battery would then become the dead battery.
The Good battery would then discharge into the dead battery.
Then the cycle would repeat over and over again.

When you put 2 capacitors in parallel and remove the battery, it is doing the exact same thing, constantly discharging and charging one another.
If the capacitors had no resistance, it would go on forever. Unfortunately, there is resistance and it does dissipate after a period of time.

Answer 3

Starts at a maximum as this is the point of highest potential, as you release the energy stored in the capacitor, the current will go to zero, as the potential goes to zero.

Answer 4

To make this more simple to understand lets say you started with two plates of metal in which a capicator is made of both having 30 electrons.30 negative and 30 positive when you charge it it puts the 30 positive on the plate that is negative.so oppisites attract so when you discharge the 30 go back in the opposite direction toward the positive attraction.