Polycarbonate capacitors are a ttpe of wound film capacitor that have been around for a number of years. The film used was first introduced as a dielectric material in 1958, and it quickly became a favorite of designers and engineers in the instrumentation, filtering, and switching power supplies fields.
They are used in numerous applications, especially those that require precision performance in their systems and they are typically used in a -55 degrees Celsius to a +125 degrees Celsius environment. They are also a preferred choice for many applications because of their stability. They are classified as a precision capacitor because of these facts.
In the last few years, however, the film has stopped being manufactured and only those companies with an adequate inventory supply of polycarbonate film have been able to keep producing these types of capacitors. For example, Arizona Capacitors Inc., has approximately a fifteen year supply of the film and will be manufacturing polycarbonate capacitors well into the foreseeable future.
The long term future of polycarbonate capacitors is questionable and eventually another kind of capacitor will step up and take its place. However, for right now, if an engineer or buyer needs these type capacitors there are still some companies that can and will supply them.