[sdiy] About tempco

Tue Apr 22 20:53:38 CEST 2003

The tolerance will depend on unit to unit variation as well.

3300 ppm might be 3600... or 3000. But if in the same lot you
have one at 3000 and one at 3600 you are in trouble. does anyone know
if these tend to be stable in the same mfg lot (likely the case of a one-time buy)

H^) harry

--------Original Message--------  

From: sbernardi at attbi.com
To: Synth-DIY list <synth-diy at dropmix.xs4all.nl>
Sent: Apr 22 2003 09:36
Subject: Re: [sdiy] About tempco

>It should work fine. The tempco tolerances (10%) don't get any worse -
>i.e., if you have a 1K @ 3300ppm/C +10% ~ +3600ppm/C, that's a 36ohm
>change over 10 degrees. If you have two of them in series both with +10%
>tempco tolerance, you get 1K + 36 + 1K + 36 = 2072, or a 72ohm change
>for 10 degrees. 72/2000/10 = 3600ppm/C, no difference.  That's worst
>case. Best case, the tempco tolerances would be equal but opposite, and
>so would cancel, resulting in an "exact" +3300ppm/C.  (that looks right
>to me. Real statistical analysis probably involves some weirder math).
>These sound VERY interesting to me.
>Michael Buchstaller wrote:
>> >Would it be possible to get these in 2 kOhm units?
>>
>> At that price, could it be possible to use 2 if these Tempcos in
>> series to get the 2K, or am i missing something here ?
>>
>> -Michael Buchstaller