Capacitance of a Capacitor

Capacitance is the ratio of the charge Q on either plates or conductors to the potential difference V between them

C = \( \frac{Q}{V} \), the unit of capacitance is farad.

1µF = 10^-6F     (micro farad)

1PF = 10^-12F    (Pico farad)

Factors Affecting Capacitance of a Capacitor

Surface area: the capacitance increases as the area increases

C ∝ A

Distance between the plates: As the distance between parallel plates of a capacitor increases, the capacitance decreases

i.e.      C ∝   \( \frac{1}{d} \) 

Dielectric material (ε): As the dielectric substance increases, the capacitance of the capacitor increases. C ∝ ε

Therefore, c = \( \frac{Aε}{d} \)