TSSP: List Archives

From: Paul
Date: Fri, 15 Jun 2001 20:15:15 +0100
Subject: Re: [TSSP] former materials

Metlicka Marc wrote:

> 3k coil-- .091" thick sona tube, no poly top coat, only insulating
> varnish
> 10-1 coil is .100" thick pvc drain pipe, insulating varnish

Thanks. Never mind the other two coils,  the most useful results are
coming from the 3k and the 10-1, so we'll concentrate on those.

> the fiberglass tanks i have are spun glass fiber impregnated with
> polyurethane resin, they are .100" thick, very uniform, and sturdy.
> if anyone wishes to wind the taped coil that you asked for, i will send
> them whatever size they wish. if this sounds suitable?

Those tanks sound pretty good, but I'll have to think a little more
about just what is required - Finn may be able to turn something on
his lathe, which would be the best solution.

> i've been looking at an inexpensive digital photometer. this says
> it is also used for demodulating optical signals for audio
> applications.

You'll need to make sure that demodulation will work right up to the
Fres of the coil.  It still think there must be a simpler way to go
about this - if all we want to do is demonstrate that a secondary 
does show a mechanical vibration, and get a rough idea of the 
amplitude.  No point in taking precise measurements of the amplitude
because we don't know how to calculate the power loss from that.
What's needed is a simple test to show that mechanical vibration is
present, that's all to begin with.  Reflecting a cheap laser light
off the coil and passing it over a knife edge or through a pin hole
some distance away would be an easy way to turn the vibration into an
amplitude modulation of the light intensity, which could be picked
up with a 50 cent light detector and viewed on the scope.  The
photometer will tell you the actual light intensity but we're not
bothered about that, only whether the modulation is there, so a 
simple detector would be adequate.

Anyway, more about the Cint issue and short coils later on the list,

Cheers,
--
Paul Nicholson,
Manchester, UK.
--


Maintainer Paul Nicholson, paul@abelian.demon.co.uk.