Re: REAL CAPACITOR (where can i buy one?)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 4/14/01 1:14:53 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes: 

Snip - - - 
>
> The active dielectric is barium titanate, which has a very high 
> dielectric constant K, anything from 1000 to 10000 depending on what 
> "impurities" have been introduced. 
>
> You'll need some titanium dioxide (this is sold under the names rutile 
> or anatase, two different crystal forms of the same stuff) enamel 
> grade (low impurities, particularly iron) and some barium carbonate, 
> as fine particle size as you can get.  I know some pottery suppliers 
> in the UK stock both of these and I assume that those in the USA do 
> too, but beware, some pottery suppliers use the name "rutile" to refer 
> to the crude mineral rutile, which has a lot of iron in it - do be 
> sure you get highly pure TiO2.  Mix them in the proportions BaCO3 197g 
> : TiO2 80g and fire the mixture.  Alternatively, you might want to buy 
> a commercial premix, though I have no idea how much it will cost you. 
> Try a websearch on "barium titanate". 


Snip - - - 
One word of caution if you mix your own. Barium Carbonate is the active 
ingredient in several popular formulations of rat poison. (BaCO3 is not 
healthy for children and other living things.) 

Matt D.