What a capacitor is made up of is 2 very thin plates separated by an insulator. The bigger the plates, the higher the Mfd. The heavier the plate and better insulator, the higher the voltage range. So, like he said, no polarity, BUT - with that said.: Some AC units have 3 connections on the capacitor. C - Fan - Herm. C would go to the power or in this case common, Fan or F goes the the fan motor and Herm goes to the compressor. Also some of the larger capacitors do have a polarity, but not in that sense - One of the terminals are marked as such as it is on the plate nearest the outside housing of the capacitor. Probably more info than you asked, but interesting for some.