Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!portal!cup.portal.com!mmm
From: mmm@cup.portal.com (Mark Robert Thorson)
Newsgroups: sci.electronics
Subject: Re: Galena Crystals
Message-ID: <24834@cup.portal.com>
Date: 8 Dec 89 22:38:13 GMT
References: <1835@naucse.UUCP>
Distribution: na
Organization: The Portal System (TM)
Lines: 14

For those who might be curious what Wood's metal is, it's an alloy
of bismuth, tin, and cadmium which can be had in forms that melt in 
boiling water.  Commonly used for the safety plug of pressure cookers
and the part which opens up ceiling sprinklers for fire extinguishing.
I hadn't known that they use it for mounting galena crystals, too.

The comment about the diode drop of a galena crystal being about 0.05 V
makes me wonder why they're aren't commercial devices with similar
performance.  Is there no application for such a thing? (Other than
crystal sets, I mean.)

And how exactly does a galena crystal work?  With such an incredibly low
diode drop, I assume there aren't any PN junctions in there.  Is it anything
like a MOS transistor with the gate and source connected together?