Re: Dialectric Constant
Tesla List wrote:
> >From rwall-at-ix-dot-netcom-dot-comMon Aug 5 20:26:29 1996
> Date: Sun, 4 Aug 1996 22:04:35 -0700
> From: Richard Wayne Wall <rwall-at-ix-dot-netcom-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Dialectric Constant
> At a hamfest yesterday, I bought a Barker and Williamson CX 62 C
> variable air condenser. It's 8"x6"x6" and made with ceramic and
> polished stainless steel plates that are 1/2" apart. The craftmanship
> is superb and it's literally a work of art. It's a shame these
> beautiful components are no longer crafted. And, it was a great buy.
> Prior to buying it, I checked it and the capacitance varies from 0.01
> to .04 nF. Yes, nanofarads. My plan is to increase the maximum
> capacitance to 20 - 40 nF by changing the dialectric and spacing
> between the plates. I am building a 3/8" acrylic housing for it.
> Changing the spacers between the plates is simple. I can even add a
> few more plates. Question is what dialectric should I choose that will
> have 500 - 1000 k and good dialectric strength? Either a gas or liquid
> dialectric would do or even application directly to the plates is a
> possibility. According to R. Hull's recent post capacitance resides in
> the dialectric only, rather than the plates. Maybe this is a place for
> Kristin's XeS6 or what ever that dialectric was. Any thoughts?
> I cannot find the recent posting of modern dialectric constants and
> their strengths. Would someone please repost it publically or
You will not find a suitable dielectric to do what you want. Only barium
or strontium titanate offer a possibility and you can't obtain these in
sheet form. There are just no real dielectrics in the K=1000 range other
than these special ceramics!!! Plus, the voltage standoff of these are
terrible!!! About 50v/mil!!
Richard Hull, TCBOR