A capacitor can be defined as a device for storing electric charges.

A capacitor is a device used to store electrical charge and electrical energy. It consists of at least two electrical conductors separated by a distance.

The capacitance (C) of a capacitor can be defined as its ability to store charges. It is the ratio of charge stored by the capacitor to the potential difference between the parallel plates. It is given as:
C = Q
V

Capacitance is measured in Farads. The capacitance of a parallel plate capacitor is also given by: C = ε_oA
d

• A parallel plate capacitor of capacitance 600μF has a potential difference of 2000V between it's plate. Calculate the charge on either of the plate of the capacitor.
solution
Q = CV
C = 600μF = 600 x 10^-6F
V = 2000V
Q = 600 x 10^-6F x 2000
Q = 1.2C
• A parallel plate capacitor of area 10cm² in vacuum has a capacitance of 10^-2μF. Calculate the distance between the plates
  [ε_o = 9.0 * 10^-12F/m].
  solution
  Where A = 10cm² = 1x 10^-4m
  d = ε_oA
  C
  = 9 x 10^-12x 1x10 ^-4
  10^-2 x 10^-6
  = 9 x 10^-7m

• Parallel Connection
When capacitors are arranged in parallel as shown in the diagram above, the equivalent capacitance can be calculated as:
C_T = C₁ + C₂ + C₃
The total potential difference flowing through a parallel arrangement for capacitors is the same
Hence is V is constant for each capacitor
The total charge in this connection is given as
Q _T = Q₁ + Q₂ + Q₃
This means the total charge flowing through each capacitor is the sum of the individual charges.
• Series connection
When two or more capacitors are arranged in series as shown in the diagram above;
The equivalent capacitance C_T is given as:
1 = 1 + 1 + 1
C_T C₁ C₂ C₃