[sdiy] About tempco

[Ian Fritz]

Hi Rene --

Hehe ...  I mean the tempco tolerance.

I made a special setup to do the measurement.  The tempco resistor and a 
thermometer are mounted next to each other in the middle of a big chunk of 
specially machined Al.  This block is wrapped with a heating pad and its 
temperature is changed slowly in steps.  The resistance change from ambient 
temperature is measured with a Wheatstone bridge circuit.  I get very nice 
straight line data -- good reproducibility, same results cooling and 
heating.  I think the measurement is accurate and reproducible to +/- 15 
ppm/K (ie., 0.5%).

   Ian


At 04:39 AM 4/23/2003, René Schmitz wrote:
>Hi Ian et al.,
>
>These are film types. Size of a regular 250mW metal film resistor.
>I could repeat my measurements with another one and probably a better 
>temperature reference.
>
>>If they are wirewound and the wire comes off the same big spool, then 
>>there will probably be very little variation.  I measured a couple out of 
>>the lot I just got from KRL and they were the same within a percent.
>
>Do you mean the tempco tolerance or the resistor tolerance?
>
>Cheers,
>  René
>
>--
>uzs159 at uni-bonn.de
>http://www.uni-bonn.de/~uzs159
>
>