[vicg1]

Originally Posted by wejones

First time I read the above, I thought you were saying that they last longer now, which didn't make sense,because having worked with PCBs, I can say that PCBs virtually last forever. But then I read it again, and I think you're saying that their shelf life now has to be considered because it is finite (smaller).
If so, interesting, I never thought of that as a reason for why modern electrolytics don't last very long. I have an old SW radio that was bought back around 1940, and it has electrolytics in it which were still good the last time I used it, which was about 10-15 years ago, so their lifetime is at least up in the 40 year range, and probably more. I never did understand why these modern devices go bad due to dried out capacitors.
I knew that PCBs were in those big AC type capacitors, like those used in florescent ballasts, but I didn't realize that they used PCBs in little DC capacitors. I'm not sure what function they would have in a small electrolytic? Ie I think the PCBs functioned as an insulator in the AC capacitors, but I thought the little DC electrolytics were made up of layers of paper soaked with electrolyte separated by insulating layers, which I woudn't expect to be a liquid, but I guess it could be paper soaked with PCBs or something.
But why would the use of PCBs make such a capacitor last longer, when I think the shelf life of the capacitor would be dependent upon the drying out of the electrolyte, not the insulator? Seems like the low shelf life would more likely be due to just not being hermetically sealed or something, rather than what dielectric is used. Anyway, just curious.

Sorry, don't know details, was told this by someone that sells caps wholesale... guess all of our TVs sitting around with dangerous PCBs in the caps just waiting to kill us got our government into gear with a ban on them...