Temp-Co resistors

Haible_Juergen#Tel2743 HJ2743 at denbgm3xm.scnn1.msmgate.m30x.nbg.scn.de
Mon Jan 8 21:10:00 CET 1996


>I used to put two 1K tempco resistors in series, available from Farnell
>Electronic Components, order number 143-584. For new designs you could
>use one 1K tempco and lower the value of the other divider resistor to
>achieve the desired 18 mV/oct scaling.

That's the way to go, for sure.
Anyway, I have seen the 2k tempcos mostly in designs where the
2k is in the feedback loop of the input summer, and the
"other" resistor(s) are the 100k summing resistors from the 1V/8ve
inputs - so You might need an extra opamp stage in that case.
Or maybe You build a low impedance voltage divider (say, with two
330 Ohm MF resistors) at the opamp's output and derive the feedback
signal from the half output voltage point. Then the summing node sees
only one half of the current it would get from the 1k tempco, just as if You
were using a 2k tempco.

JH.



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