Are these miniature 0.3 F gold caps for real (see photos) ?

 

Hello,

The device is for a short time buffer.
See this page for more info:
https://www.zimo.at/web2010/products/energiespeicher_EN.htm

Bertus

 

Thanks. I just thought 300.000 uF would have to be much larger ?

 

new ultracapacitros are getting smaller and smaller. here is 100x larger value in a tiny package (8mm diameter, 16mm height)
https://www.mouser.ca/ProductDetail/ABRACON/AHCR-S04R0SA306Q?qs=jRuttqqUwMR84qKkiVIyJw==

 

Crazy

 

0.3 F = 300000 μF

 

I would encourage you to read the Wikipedia article on supercapacitors, as there are different variants. Some are suited for memory back up applications, others to absorb short high-energy bursts from a motor-generator.

Supercaps are not meant to replace standard electrolytics for filtering rectified AC.