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Re: Doorknob capacitors for primary?



Original poster: dhmccauley-at-spacecatlighting-dot-com 


Most doorknob capacitors are of ceramic type and very high dissipation (High
ESR) type capacitors.  With repetitive charge / discharge cycles as in tesla
coil use
they will heat up and fail or at worst explode.

However, there are some types of doorknob capacitors that do work well.
These include MICA transmitting type doorknob capacitors and there are a
very few types of
ceramics that can work in tesla coil use as well.  (TDK "brown" ceramics
seem to work okay at least for VTTCs.)

But for the most part, ceramic doorknob capacitors in general are bad and
should be avoided.

Dan


I was wondering why I don't see many coilers using ceramic "doorknob" HV
caps for their tanks?  Are they more prone to failure?  I just happened upon
a parcel of 18  570pF 40KV caps, and I bought the lot of them. I'll be
running them on a 15KV 60 NST.   I'm looking to build a bipolar coil using a
nice pair of  5 1/4 by 31 inch long fiberglass coil forms I just found, and
was wondering if I should have to incorporate some kind of blast shields
into the designS