[Re: thermal tips re expo converters:]

[Haible Juergen]

	>Probably the truth lies somewhere inbetween. First, I don't know
whether >the
	>tecniques of "thermal isolation" will make the cooling rate to slow
to be
	>practical. 

In correction to my earlier post, I have to agree with Martin and Ian.
The thermal capacity would not be changed by isolation, but the
thermal resistance is increased. Thus the "release" time constant
of the system is increased. In theory, you could still get a stable
system by adjusting the "attack time constant" (heater current)
and the gain & time constant of the regulation loop to get it stable,
but in the end you'd have a much slower regulation. You save energy, 
but your regulation becomes slow. 
I still have to think about whether slow regulation and higher impedance
to the "error source" (ambient temperature) would somehow cancel
for short fluctuations of ambient temperature. (?) But the warm up time
would be much increased for sure. 
I think temperature *compensation* + isolation is the best solution.

JH.