[time-nuts] temperature sensor
brooke at pacific.net
Mon Jul 21 16:11:53 EDT 2014
The temperature of steam can be anything above boiling water.
Super heating of steam was common railroad practice.
Boiling pure water will get rid of any trapped gases quickly.
In fact this is the recommended thing to do to tap water before using it for freshly cut roses.
Of course you need to let the water cool before putting them into it. Removing the trapped oxygen makes them last longer.
Alan Melia wrote:
> er not boiling water....steam. Water's boiling point is affected by the dissolved gasses and other contaminants.
> ----- Original Message ----- From: "Bill Dailey" <docdailey at gmail.com>
> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
> Sent: Monday, July 21, 2014 5:43 PM
> Subject: Re: [time-nuts] temperature sensor
>> Ice water and boiling water coupled with altitude will give you two points.
>> Sent from mobile
>>> On Jul 21, 2014, at 10:12 AM, Attila Kinali <attila at kinali.ch> wrote:
>>> On Mon, 21 Jul 2014 04:39:51 -0700
>>> Alexander Pummer <alexpcs at ieee.org> wrote:
>>>> NTC are not that very stable, they are amorphous material winch could
>>>> recrystallize slowly and therefore change it's electrical behavior ,
>>>> PT100 style is more reliable since it is pure metal
>>> How long is the time constant for NTCs?
>>> I guess, it wouldn't matter for most of the measurements we do,
>>> as NTCs need to be "calibrated" before precision measurements
>>> anyways. Unless one measures over several months, or years.
>>> But on this timescales, i wouldn't really trust an off the shelf
>>> PT100 either. Not unless i measure its stability
>>> For use in GPSDOs and OCXOs, i guess it doesn't really matter,
>>> as long as the NTC stays within spec. There an external loop
>>> corrects for the variation/drift of the measurement.
>>> While we are at it: what is a good way to calibrate/characterize
>>> temperature sensors that is available to hobbyists?
>>> Attila Kinali
>>> I pity people who can't find laughter or at least some bit of amusement in
>>> the little doings of the day. I believe I could find something ridiculous
>>> even in the saddest moment, if necessary. It has nothing to do with being
>>> superficial. It's a matter of joy in life.
>>> -- Sophie Scholl
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