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Re: Cooling your components

> Original Poster: "christopher boden" <chrisboden-at-hotmail-dot-com> 
> 
> 
> >Has anybody tried cooling the components in liquid nitrogen?
> 
> Great Idea! Bad Plan :-(
> 
> Plus:
>     Liquid Nitrogen is about -400F so it would DEFINATELY cool your 
> componentry. (And look Really cool while doing it)

generally referred to as 77Kelvins, BTW... It depends on the pressure
also.. Inside that big High Pressure (235psi) dewar it is somewhat warmer.

> 
> Minus:
>       Supercooling electronic components (and anything else) tends to 
> DRASTICALLY alter physical properties (Conductance, hardness etc...).
> Most superconductors have to be supercooled in either liquid nitrogen ot 
> hydrogen (even colder, as far as I know the coldest their is).
Liquid H is about 22K, slush H is somewhat colder and denser, Liquid He is
colder yet (4K, nominal).

Actually, very few superconductors work at even liquid H temperatures,
hence the intense interest in the High Temp Superconductors (at LN2 temps).
Most run of the mill superconductors are run in liquid He (all those
Niobium Tin alloys, etc.)

> The internal structural stress from the change in temp could damage 
> things as well. I've played extensively with liquid nitrogen (I build 
> lasers for fun) and have seen some REALLY unusual things happen when you 
> deep-freeze something.

Particularly if you cool it fast, like plunging it into LN2.  The very cold
temperatures also cause changes in the crystalline structure of the metals.
Most steel gets quite brittle at LN2 temps.

>  If you get the chance...try dipping an *EMPTY* 1 gallon metal can into 
> liquid nitrogen, just make sure the caps on tight.
> Have fun.

Interestingly, I have contemplated using LN2 as an insulator/coolant. It is
easy to get in a relatively pure condition which improves the breakdown
voltage, and, as a benefit the resistance of the copper conductors is
substantially reduced. And, it is cheap (about $2/gal).  The nice thing,
compared, to say, oil, is that when you spill it, it evaporates clean.