Capacitors are electronic components that have the ability to store or electrical current flow for a while. Its value is usually greater than 1 μF. Greatest voltage stamped on the body.
Capacitors ability to store charge is called capacitance (C), Capacitance is measured in terms of the charge that can be stored in an increase in voltage.

The amount of capacitance is expressed in units of farads (F). In practice unit Farad (F) is considered very large, so the unit usage reduced to Micro Farad Farad (μF), Nano Farad (nF), Piko farad (pF). Capacitance is defined as follows:
Which is:
C = Capacitance (Farad)
Q = electric charge (Coulomb)
V = Voltage (Volt)

Capacitors are typically associated surface shaped flat plate. Widely depending on the size of the capacitor plate area (A), the distance between the plates (d), and the insulation field.
The composition of the condenser is composed of two pieces of coated conductors by a kind of insulation is called the dielectric (ε0) as shown:

As shown in the figure, the capacitance can be calculated as follows:

Which is: 
C = capacity of condenser (Farad)
ε0 = dielectric constant (Farad / meter)
A = cross-sectional area or field plate (m2)
d = distance between the plates (meters)