Why do some capacitors have polarity?  (Asked once already, but
for some reason was not visible.) That is sort of a blanket
question. I'm wondering: 1) why only some, and not all or none?
2) what (in their physical structure) causes them to have
polarity? 3) why do we make ones that have polarity? Is there
something prohibitive, like cost, or safety, making it so in the
production? (okay, not safety, as may attest anyone who has seen
a reversed capacitor explode.)  whizz1234 years ago Capacitors
are measured in the unit called the Farad. Condensers are also
capacitors. It refers to the amount of charge a capacitor can
store. That unit, the Farad, is very very big and poorly chosen.
Most values you come across are microfarads. The microfarad is
one millionth of a Farad! So you can see how big the Farad is.
The pico farad is also use in radio work and other applications.
This is one millionth of a microfarad! So you can see even more
so the size of a Farad. To get large value you need to use
electrolytic capaci