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Glass plate capacitors



Hi Scott,

Original Poster: "Scott Stephens" <Scott2-at-Mediaone-dot-net>
> 
> Who has used plate glass for their capacitor, what specs and what results? I
> remember someone complaining a while back it was very heavy. I'm considering
> stacked plates with aluminum foil in between:
> 10" x 10" with 1/4" on the edges painted with corona dope
> .05" or .1" thick plate glass for 12KV?
> 
> Thanks,
> 
> Scott

    The first time I tried glass plate capacitors (1/8" window glass) with
aluminum foil they broke and took the neon sign transformer (12/30) with
them.  Fortunately I was wearing safety glasses at the time! I noticed that
the broken pieces of glass were hot to the touch.  I made another glass
plate capacitor with galvanized iron sheets and got a new transformer.  The
conductivity was not so good but the heat conductivity was better than
aluminum foil.  They never broke.  

    At a later time I tried blue acrylic sheets (1/4" thick) with 1/8"
thick aluminum plates (edges rounded off and polished).  They worked good also.

    Glass and acrylic sheet (perspex? for those on the other side of the
pond) are very lossy.  They are not good choices for capacitors used in RF
work.  You can make a much better capacitor for $20 to $30 with
polypropylene Multiple Mini Capacitors.  

Cheers,
Barry