Cob RE: evaluating road gravel slab

[John Straube]

On Saturday, January 30, 1999 11:34 PM, Keith Breuker 
[SMTP:flyfisherkb at centuryinter.net] wrote:
> I'm looking for three or four temperature sensors that I could bury at

> Does anyone have knowledge of such things that could make a
> recomendation?  I don't want to spend much if it can be avoided.

I would recommend a precison 10k ohm thermistor.  These can be measured 
with a standard multimeter and sensor leads made of normal light gauge 
telephone wire work fine. Such thermistors can be pruchased for a couple of 
dollars at an electronics supply house.
The tough part is to plot the curve of resistance vs temperature.  If you 
buy expensive ones, this curve is provided.  If you buy cheap ones, you 
make the curve by measuring the resistance at, say, 0 (in ice bath), 10 C, 
20 C etc.  You can decide yourself how much time vs how much money you wish 
to invest.
Use shrinkwrap tubing around all your underground connections to avoid 
corrosion.

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John Straube
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