In sci.electronics.design Tom Biasi wrote:
On 9/27/2012 3:44 PM, Jim Thompson wrote:
AC Cap Dropper DC Power Supply

Anyone know of a clever way to regulate other than the typical
brute-force zener clamp?

...Jim Thompson




A long,long time ago in a place not so far away I used a transformer
made by Sola that had a matched resonant capacitor.

ferroresonant transformer- they're peculiar beasts.