Electrolytic equals DC device.
Electrolytic Caps equal DC usage.
NON-POLARIZED Electrolytic Caps may be used on AC Circuits.
Start & Run Caps were typically Non-Polarized Electrolytics, as were Power Factor Correction Caps.
Now I believe there are options for "OK Caps" (Non-Polarized Electrolytics), and "Better Caps" (Polypropylene, etc.).
The last Start Capacitor I replaced - apx. 1998, was a Non-Polarized Electrolytic (the replacement item).
HID Ballast Caps were mostly all "Wet" Non-Polarized Electrolytics (pre-year 2000), but now they almost universally use "Dry Film" Caps, which I would
imagine are something in the Mylar realm.
"Cheap-O" Crossover Caps are Non-Polarized Electrolytics.
Better quality X-Over Caps are Non_Polarized Polypropylene, and Mylar.
Scott
