Hi, what is the difference between polarized & non-polarized capacitor? why & where do we need a polarized capacitor? What happens if a non-polarized capacitor is connected instead of a polarized?

 

Polarized capacitors are used because they have a higher capacity due to they way they are made - http://www.allaboutcircuits.com/vol_1/chpt_13/5.html.

A non -polarized capacitor will substitute with no problem, but you may have trouble finding one with the same value that isn't a lot larger and more expensive.

 

Non polorized caps are where polarity changes [AC] as in motor starting, audio crossovers neteorks; polorized caps need predomently DC of correct polarity. Sometimes two polorized caps are connected + to + or - to - to synthisize a polar cap for low level AC.