This is a multi-part message in MIME format.
--------------010609040709020806070504
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Never thought that my little cct would provoke such a lengthy debate. No 
bias intended but I agree with Russells' comments. The whole cct costs 
less than $1.20 (AUS) to build (obviously labour is not included). We 
buy the TL431 in the hundreds, and blow them up in the hundreds (I 
should clarify, the students do). And with a minor mod, will function on 
AC voltages just as well ;)

Antonio Benci.

> 
> Simpler, perhaps a little.
> Cheaper, probably not.
> Efficiency is not liable to usually matter much in this 
> application.
> But the FET solution will be less accurate and less 
> repeatable and less flexible.
> 
> The TL431 is fully programmable for voltage across its 
> specified range, with various accuracy versions available 
> (typically 0.5%, 1%, 2% AFAIR). It is cheap and very 
> available.
> 
> 
>         Russell 
> 

--------------010609040709020806070504
Content-Type: text/x-vcard; charset=utf-8;
 name="nino_benci.vcf"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
 filename="nino_benci.vcf"

begin:vcard
fn:Antonio Benci
n:Benci;Antonio
org:Monash University;School of Physics
adr:;;PO Box 27;Monash University;VIC;3800;Australia
email;internet:nino.benci@sci.monash.edu.au
title:Professional Officer / E&IS Manager
tel;work:+613 9905 3649
tel;fax:+613 9905 3637
x-mozilla-html:FALSE
url:http://www.physics.monash.edu.au
version:2.1
end:vcard


--------------010609040709020806070504
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

--------------010609040709020806070504--