[sdiy] tempco resistors

[pata at ieee.org]

Hi Lists!

Yes, I'm still selling +3300ppm TMPCOs 40 JPY each.
Anyone want to buy, contact me off-list.

Taku

Louis van Dompselaar wrote:
> That was what I was thinking.  I hadn't seen 3900ppm/K recommended before.
> 
> I use the 3300ppm/K ones that were sold on this list by Taku at 40 JPY 
> each.
> 
>>> Not quite the 3900ppm/'C that is usually used, but a lot better than 
>>> nothing!
>> Actually the ideal tempco resistor has a resistance that is 
>> proportional to absolute temperature T, as it has to compensate for an 
>> effect in the expo pair that is inversely proportional to T.
>> This means at 25 degrees centigrade, i.e. 298.15 K, a tempco of 
>> 1/(298.15) = 3354 ppm/'C.
>>
>> Therefore a resistor with 3900ppm/'C is more off than one with 
>> 3000ppm/'C by itself. However, you can combine it with a series or 
>> parallel resistor to lower the tempco. This easy method of correction 
>> is not possible if you have a lower tempco to begin with.
>>

-- 
===================================================
KATAYAMA, Takuya
Muse Music Synthesizer Laboratory, TOKYO