group buy for homebrew CPUs?

[Chuck Guzis]

On 8/12/2006 at 3:02 PM Don wrote:

>Do they still use thermocouples (dirt cheap)?  Or, have
>they moved on to things like infrared, etc.?

I've been out of that area too long.  This was when I was a YOUNG man.
That was the day of mechanical chopper-stabilized vacuum-tube amplifiers,
some running from 25 Hz mains power.  Heck, some places back then still had
key-wound chart recorders wtih clamp galvanometers. (Somehow, the word got
out that the galvanometer supports were gold, so we'd usually have to come
by a couple times a week and replace them).  For some burner control, I do
recall some optical quartz-lensed thermopile heads, but they weren't
common.  You checked accuracy of thermocouples with a hot-wire optical
pyrometer and calibrated instruments with a potentiometer bridge and a
thermometer (to measure the cold-junction temperature).  Weston standard
cells were still in use. 

Cheers,
Chuck