Re: [humidity gauges]

From: 	Kevin Christiansen[SMTP:kevin+-at-cs.cmu.edu]
Sent: 	Tuesday, December 09, 1997 10:57 AM
To: 	Tesla List
Subject: 	Re: [humidity gauges]

At 11:35 PM 12/6/97 -0600, you wrote:


>From: 	Jim Lux[SMTP:jimlux-at-earthlink-dot-net]

>Sent: 	Saturday, December 06, 1997 11:30 AM

>To: 	Tesla List

>Subject: 	Re: [humidity gauges]



>> A few months ago Fair Radio Sales, Lima, OH, had some nice 6 inch dia.

>> humidity gauges for about $10.  We added one to the lab wall about 3


>> ago and it works great -- use it more for checking performance on Van de

>> Graaffs than on TC's, but you can always check the RH in your lab and the

>> cost if reasonable.


>Radio Shack also has battery powered hygrometer/thermometer combinations

>for about $20. We make clouds and fog a lot at work, and find that the RS

>units work just fine for standardizing conditions. Of course, they aren't

>sensitive to glycol vapors which is what we use for some fog, but, oh



If you want precision at low humidities, the Radio Shack unit doesn't

cut it.  I can't get my Radio Shack unit to read less than 19% humidity

no matter what I do (and that includes enclosing it in a jar with

1/4 pound of just-dried anhydrous calcium sulphate, which is a very

powerful dessicant).

Just so you know....

- Kevin Christiansen


                     Kevin D Christiansen

Human Computer Interaction Institute - Carnegie Mellon University

      kevin-at-cs.cmu.edu    http://www.cs.cmu.edu/~kevin/

"The universe is composed of space, galaxies, and intergalactic

 dust.  Galaxies themselves are composed of space, stars, and

interstellar dust.  From the omnipresence of dust, we conclude

that nature abhors a vacuum and won't pick up a broom, either."