Path: utzoo!attcan!uunet!husc6!rutgers!iuvax!silver!commgrp
From: commgrp@silver.bacs.indiana.edu
Newsgroups: sci.electronics
Subject: Diodes in liquid nitrogen
Message-ID: <7200024@silver>
Date: 23 Dec 88 14:44:00 GMT
Organization: Indiana University CSCI, Bloomington
Lines: 29
Nf-ID: #N:silver:7200024:000:1092
Nf-From: silver.bacs.indiana.edu!commgrp    Dec 23 09:44:00 1988



>In article <7200022@silver> commgrp@silver.bacs.indiana.edu writes:
>>RS catalog # 276-087 "Super-Bright LED" ($1.69, from Japan) is truly 
>>impressive.  It's rated 2000 mcd output at 20mA (red; wavelength 660 
>>nm).

>Of course, the *REAL* question is:  How do they perform when 
>immersed in liquid nitrogen?

>Original LEDs had a significant increase in efficiency when 
>supercooled... Unfortunately, the high efficiency LEDs (40mcd) I 
>tried didn't have the same effect.  It would be interesting to 
>know if these new LEDs do.  They would be really impressive with 
>several hundred mA of current at significantly higher efficiency!

>--Charles  flaig@apple.com

Other semiconductors work better at liquid nitrogen temperatures 
too.  I once worked for a manufacturer of silicon rectifiers 
which made a water-cooled 1000-Amp unit with a single enormous 
alloyed junction (which couldn't be duplicated when they changed 
to a diffused-junction process).  A cyclotron facility in 
California got 10,000 Amps through these by cooling with LN2.

--

Frank
reid@gold.bacs.indiana.edu