A  Capacitor or a Condenser is a device for storing charge. A combination of two conductor plates of area A, put closed to each other separated by a small distance d is called a capacitor. Add caption These plates could be of any shape -a sphere ,cylinder or flat plate. The geometry of the capacitor plates determines the capacitance for a given plate conductor area. Usually the space between the plates is filled with a dielectric medium of relative permittivity ℰ. The earliest capacitor was invented accidentally by Van MUSSCHENBROEK of Leden in about 1746 and became known as a Leden Jar. Technically any conducting material has some resistance,capacitance and inductance . If we put some charge on a piece of aluminium foil it will retain it until someone touches it or somehow it makes contact with a nearby substance,however its charge storing capacity is very limited since excessive charge density will lead to Corona Discharge. A marvelous example of such capacitor is Van De Graff Ge...