Re: A Simple Lab Demo of Resistor Noise EMF.

[Bob Sciamanda <trebor@VELOCITY.NET>]

You've got it right, Brian.  What I described goes by the name "hot wire"
ammeter.
http://www.tpub.com/neets/book3/7a.htm  is a comprehensive collection of
various meter movement technologies, with good drawings, suitable for
class use.

Bob Sciamanda
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: "brian whatcott" <inet@INTELLISYS.NET>
To: <PHYS-L@lists.nau.edu>
Sent: Wednesday, March 21, 2001 01:06 PM
Subject: Re: A Simple Lab Demo of Resistor Noise EMF.


> Actually, "taut-band" is the usual description for the way a pivotless
>  meter construction holds a moving coil in the field, for example.
> The term is also used for an optical shutter pivotless construction.
>
> In contrast, a hot wire ammeter may well feature an orthodox
> jeweled pointer pivot.
> Here's a current offering in the former category.
>
> <http://www.beede.com/panel_meters_magcentric_taut_band_b_c.htm>
>
> Brian
>
> At 10:34 3/21/01 -0500, you wrote:
> > This is called the "taut wire" ammeter.  A stretched wire, with
attached
> > pointer, carried the current.  The wire changed length in response to
I^2R
> > heating.
> >
> > Bob Sciamanda
>
> -----------
> > > There was another instrument in the same general class:
> > > the hot wire ammeter relied on the sag caused by current
> > > through a fine wire to provide a pointer deflection.
> > > It was indifferent to the current direction.
> > > brian whatcott
> brian whatcott <inet@intellisys.net>  Altus OK
>                 Eureka!