[time-nuts] uC ADC resolution (was: Poor man's oven)

[Attila Kinali]

On Wed, 7 Jun 2017 22:20:50 +0100
Peter Vince <petervince1952 at gmail.com> wrote:

> > Additionally: if I would set out to build my own OCXO today, I would
> > go and buy one of those lunch thermos flasks to house everything. Their
> > isolation is higher than anything you can easily build yourself,
> > especially at that size. I would place the (inner) oven at the bottom,
> > probably using a puck design similar to the E1938, place the electronics
> > on top of it and close the lid using an aluminium plate which forms
> > the outer oven.
> 
> Might there be a problem that a thermos flask is TOO well insulated, and
> even the minimal heat generated in the electronics would be more than could
> escape through the vacuum, and so the unit would cook?

That's why the top of the flask is closed with an aluminium plate.
Assuming the plate on the top is around 5x5cm, that should give a
thermal resistance in the order of 20-40°C/W. That's not low, but
should be enough to support 100-400mW of heat generated inside
with a moderate temperature differential. If it turns out not to
be enough, making the plate bigger and attaching a few fins, or
having a small fan blowing lightly on it should solve the problem.


			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