[sdiy] Measering KTY81-110

[René Schmitz]

Hi Harald,

> if i look at my data and the datasheet of KTY81-110 there is something wrong. 
> When the datasheet is right, what i asume,  then i have an constant error in 
> my data or a bunch of bad KTY's. The error is +250R. But when i draw the 
> lines and subtract the constant error i can see that they are close to the 
> datasheet and pretty linear in the interesting range. Think i have to 
> control/calibrate my tempsensor. Needs boiling water and ice. 

I tried to make some sense of your table, but I don't know what the 
individual columns are for. Are these several devices, or individual runs?
Also the values are probably not in ohms but "deziohms". :-P

Other than that (assuming the values you listed are to be divided by 10) 
they look quite close to the theoretical 1000.0 ohms at 25°. I can't see 
an error of 250 ohms there, if that would be the case your measurements 
at 19.5° and 28° would be about 11000..13000 not between 9865..10757. 
Probably you need to place the decimal point on that error as well, and 
its more like 25 ohms which would be well within the limit of tolerance.

>>Here wat i got deg in C R in Ohm
>>
>>
>>c		1		2		3		4		5
>>
>>-18		7447	-----		-----		-----		-----
>>17,5		9717	9770	9773	9778	9729
>>19, 5		9888	9905		9881	9865		9851
>>28			10438	10445	10427	10415	10387
>>32,5		10730	10757	10739	10714	10683
>>34,5		10901	10929	10908	10885	10852
>>38			11219	11249	11228	11202	11169
>>41			11452	11481	11461	11436	11399
>>43,5		11702	11723	11691	11683	11647
>>46,5		11920	11992	11955	11944	11905
>>50			12347	12365	12314	12299	12261
>>55			12851	12870	12815	12785	12735

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159