On 6/4/17 10:01 PM, Chris Albertson wrote:
Voltage is proportional to the product of resistance and absolute temperature. As an experiment place a voltage across a high value resister like say one 1M raise the volts until you are near the limit of the resister and connect it via a coupler cadaster to an audio amplifier. You will hear white noise in the speakers.
As in Johnson noise - vrms = sqrt(4kTR)
There is a similar effect in semi conductors. The best example of this is visual noise in digital camera, when you tern the gain way up (set the ISO high) you can see it in the photo.
I believe that's a different mechanism, shot noise.
All of this is proportion; to absolute. As I remember we ran the "oven" at -20C There was a valve used to flash out the air inside with inert welding gas to reduce ice. Some people use vacuum and get to cryogenic temperatures. But that is expensive and way-hard without an institutional size budget.
cryogenic (as in LN2 temps) is very hard with TEC it takes many stacked devices that wind up looking like a ziggurat.
near vacuum isn't that tough at home - refrigeration vacuum pumps are inexpensive. If it's a one time thing, a sorption pump and one time Ln2 or Dry Ice can get you pretty empty as a one shot. Then you seal it off and it's done. the Bell Jar - http://www.belljar.net/ is a handy reference of vacuum hacking stuff
What is the reason why you'd expect less noise with a TEC? Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there.
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