Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!hao!boulder!sunybcs!kitty!larry
From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: rec.audio,sci.physics,sci.electronics
Subject: Re: Mercury Filled Speaker Wire
Message-ID: <2016@kitty.UUCP>
Date: Fri, 18-Sep-87 22:35:56 EDT
Article-I.D.: kitty.2016
Posted: Fri Sep 18 22:35:56 1987
Date-Received: Sun, 20-Sep-87 06:44:32 EDT
References: <1538@culdev1.UUCP>
Organization: Recognition Research Corp., Clarence, NY
Lines: 26
Summary: Not a very large change...
Xref: mnetor rec.audio:3333 sci.physics:2211 sci.electronics:1360

In article <1538@culdev1.UUCP>, drw@culdev1.UUCP (Dale Worley) writes:
> > 	Actually, you have touched upon a grain of truth.  Mercury-filled
> > tubing - expecially of the silicone rubber variety - makes a simple, but
> > effective position transducer.  As the cable is stretched, both the length
> > of the mercury column increases and its diameter decreases in the affected
> > area; this results in greater electrical resistance as the tubing is
> > stretched.
> 
> Though, since the resistance of the cables is around 0.1 ohm, and the
> speakers are around 4 ohms (they used to be, has this changed?  and is
> this DC or AC resistance?), the bulk of the voltage drop is across the
> speakers.  Or is even such a small effect (if it has an audio period)
> audible?

	Mercury-filled tubing forms a simple one-axis/one-element strain
gage transducer.  Its gage factor (strain sensitivity) is pretty small
due to the comparatively small resistivity of mercury.  Gage factor =
(delta_R/R)/(delta_L/L) where (delta_R/R) = resistance change, and
(delta_L/L) = strain.
	Is the strain gage effect audible?  To normal, objective people:
hell, no!  To "Golden Ears": hell, yes! :-)

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231       {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}   "Have you hugged your cat today?"