[sdiy] Sonic qualities of parts..

[George Hearn]

This very good document from wolfson microelectronics gives a good round up
of capacitor types to be used in audio..
http://www.wolfsonmicro.com/uploads/documents/en/WAN0176.pdf


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Neil Johnson
Sent: 17 September 2008 10:18
To: Paul Perry; synth-diy at dropmix.xs4all.nl
Subject: Re: RE: [sdiy] Sonic qualities of parts..

Hi,

"Paul Perry" <pfperry at melbpc.org.au>
> They are also magnificently microphonic.
> One of the electronic mags ran a project for an "engine repair"
stethoscope,
> using one glued to the end of a screwdriver as a microphone for listening
to
> suspicious car sounds.

Both the voltage-dependence and microphony are due to the piezoelectric
properties of the ceramic dielectric.  In the former, the applied electric
field distorts the physical dimensions of the capacitor, reducing the
capacitance.  In the latter it is acting as a crystal microphone.

Neil


--
http://www.njohnson.co.uk

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