An electrolytic capacitor is composed of a metal layer and a conductive polymer (the electrolyte). In between lies a thin metal oxide layer that serves as an insulating layer which serves as a dielectric.
The electrolytic capacitor has, due to its design, some special properties...
The amount of energy a capacitor can hold is called capacity. The unit of capacity is Farad (symbol F). In circuit diagrams and formulas a capacitor is represented by a C.
In practice, capacitors have much lower capacity than 1 farad ...
1 millifarad = 1 mF = 0,001 F
1 mikrofarad = 1 μF = 0,000 001 F
1 nanofarad = 1 nF = 0,000 000 001 F
1 pikofarad = 1 pF = 0,000 000 000 001 F