Hardware description of capacitor

A capacitor is a small piece of electrical hardware which stores an electric energy or current within a circuit or field.It have two metallic plates which is separated by a conducting material i.e dielectric.

Basically capacitor have two terminals or legs:

Non-Polar capacitors have no polarity so we can use any terminal as positive or negative.

Polar capacitors have polarities(positive and negative). 

Positive = Longer terminal.

Negative = Shorter terminal