[sdiy] Tempco 2k +3350ppm Group buy

[Ian Fritz]

At 06:52 PM 5/22/06, Grant Richter wrote:

>I was under the impression from previous discussions that the tempco
>changed with temperature and 3300 or 3500 etc. was just an
>approximation for room temperature.

Yes.  The difference between 3500 and 3300 is 6%, whereas the accuracy of 
the tempco is generally 15%.  So at that level of approximation, 3300 and 
3500 are about the same.


>I have noticed this in actual VCOs that the slope changes slightly
>with temperature.

Usually this is because the tempco is incorrect.  But there are also 
contributions from linear drift in the VCO core, and small contributions 
from nonlinear tempco resistance.

It's an amazing experience to compensate a VCO very accurately and see no 
change in scale at temperatures up to 35C (90F).  Not worth the trouble 
for  everyday use, perhaps, but almost spooky.

   Ian