Re: temp. calibration of CBL

[gastineau@badgerden.com (John E. Gastineau)]

Well, there's another problem. Using the Vernier temp probe (not the 
TI probe that comes with the CBL unit) and the CBL, the available 
resolution is 0.29C. (Using a ULI or SBI and a computer, the 
resolution is 0.073C.) So, an extremely good calibration may not be 
worth the time. 

I have a cbl running both the Vernier standard prrobe and the TI
probe right now. The TI  probe seems to have better resolution,
about 0.1C (but not consistently--I'm not sure why), since it uses
the cbl in resistance rather than voltage mode. 

As far as the noise Robert Harris found, I suspect a poor connection 
somewhere. I see no such fluctuation; instead, I see readings 
bouncing one up and one down from a center digital step. 

On  2 Jan 97 at 15:51, Robert W. Harris wrote:

> At 12:03 PM 1/2/97 -0600, you wrote:
> > A biologist in our college wants to measure the temperature of
> > ambient air within a cave to monitor its effect on bats.  I offered
> > to do this for him with Vernier temperature probes and a Texas
> > Instrument CBL.  We want to calibrate the probes with a little more
> > accuracy than we can get using the freezing and boiling points of
> > water.  Does anyone know of any materials whose melting and/or
> > boiling points are in the vicinity of 15 C and whose value is known
> > well enough to provide calibration to within 0.2 C?  Jim Riley,
> > Department of Physics Drury College 900 N Benton Ave. Springfield,
> > MO 65802 e-mail: jriley@lib.drury.edu Phone:  (407) 873 7233
> I'd be interested in hearing how repeatable your data is.  We left
> the original temperature probe in open air and made measurements
> every few seconds until we accumulated 99 readings (the limit of the
> TI 82). The range was more than 3 C deg(!) The readings were in no
> particular order (not always rising or falling).
>
> Did I miss something?
> Bro. R.W.Harris                    (Voice) 617-323-7333
> Catholic Memorial High School       (fax)  617-325-0888
> 235 Baker Street              email rwharris@k12.oit.umass.edu
> West Roxbury MA 02132

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John E. Gastineau
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