Consider the two plates in a Parallel Plate Capacitor , we will assume that these plates are an exact copy of each other. Lets say that the top plate is connected to the positive terminal of a battery whilst the bottom plate is connected to the negative terminal of a battery.

To calculate the total charge stored on the top and bottom plate we would take the amount of charge and divide it by the area of the plate - this would tell us how much charge is spread over the plate.

The top plate in this case would have Q/A amount of charge on its surface. The bottom plate would have

- Q/A charge on its surface, the negative sign shows negative charge from negative terminal of the battery.

Keeping the above in mind I'd like to point out a useful concept that is the Flux density (

**D**) = ε

**E**, Therefore

**E**=

**D**/ε, Now what might not have been discussed earlier it that the electric flux density (

**D**) is how dense the charge is or how much charge there is in a given area so

**D**= Q/A.

With that in mind

**E**becomes;

**E**= Q/εA.

Ok now back to Capacitance, well as stated in another thread Capacitance is the ratio of Charge (Q) to Voltage (V) or

C = Q/V. Now also from previous discussions is was found that V = E. d, and

**E**(From above) = Q/εA therefore putting it all together we get: C = Q/V = Q / (Qd/εA) flippling side Qd/εA to give a product as you would do in fractions to give:

C = Q * (εA/Qd) = QεA/Qd, now the Q's cancel out giving the result, C = εA/d.

Here we see that the Capacitance then is not dependant by the amount of charge there is or voltage, but by the Geometry (Shape) of the component itself.

Nirvana.