Integrating Capacitor

[Tony Clark]

> 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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I can't drive (my Moog) 55!         |     The E-Music DIY Archive
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From: "List, Christopher" <Chris.List at sc.siemens.com>
To: "'Paul Perry'" <pfperry at melbpc.org.au>, synth-diy at mailhost.bpa.nl
Subject: RE: alps pots
Date: Fri, 5 Feb 1999 11:30:55 -0500 
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Parametric EQs use center-tapped pots (see the rane www site). Which is
cool, I've been wanting to build a para-EQ.

Anyone know of a US supplier?

- CList

> -----Original Message-----
> From:	Paul Perry [SMTP:pfperry at melbpc.org.au]
> Sent:	Friday, February 05, 1999 8:09 AM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	alps pots
> 
> quite small footprint. Also, the track is CENTRE TAPPED, so you 
> can do wild things, like choose between 2 different modulation sources,
> instead of crossfading between them.  Apparently they are intended for use
> in some particular type of tone control.
>