[sdiy] expo accuracy? or integrator accuracy?, or both?

[Ian Fritz]

At 10:23 AM 2/7/2003, Grant Richter wrote:
> > What is the objection to mica? I have never understood that. Cornell
> > Dubilier specs some units at 25 ppm/K drift.  The good "pure India ruby
> > muscovite mica" units cost several dollars.  Other grades may be inferior.
> >
> > In addition to the absorption (dissipation) effect you note, there can also
> > actually be hysteresis or memory effects.
> >
>
>You might also want to look at Glass-Ceramic COG types 0 ppm +/- 30 ppm.
>Corning used to make them for the Space program.
>
>Not sure the difference between COG and NPO, have tried both in place of
>polystyrene with equivalent tracking performance.

Grant --

I hear that glass and teflon are also real good. But not that easy to 
obtain or even use (glass caps are huge physically).

   Ian