Integrating Capacitor

[Tony Clark]

Note:  Sorry if this is a double post, I never saw it come through on my 
end.  -- Tony

> what is the typical performance of a mica compared to polystyrene?  leakage?
> temp. dependance?

   According to Cornell Dubilier, a leading Mica manufacturer, these are 
the specs for their Mica caps:

Full voltage range capacitance change    : +/-0.1% (0 to max rated voltage)
Full temperature range capacitance change: +/-0.5% (-55 to 125C)
Dissipation factor maximum               : 0.0014 @ 1kHz
Series inductance                        : ~8nH

   You can find this information at:  www.cornell-dubilier.com

   For polystyrene caps, I went to Xicon's site:

Full temperature range capacitance change: +/-0.5% (-40 to 85C)
Dissipation factor maximum               : 0.1% @ 1kHz

   Other information wasn't listed.  You can find this information at:
www.sourceresearch.com/xicon/film.htm

   SI shows that their polystyrene caps have a dissipation factor of 0.04 
max.

Find it at: www.seacorinc.com/Tables/precision.htm

   Well that was all I could find in short notice.  From what I can see, 
both types share very similar specs.  There are a number of references 
that claim Mica to be the best insulator material available.  So to me, 
this seems like the best choice for small value caps.

   Tony

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