Author Topic: Analog tempco compensation for ZnO gas sensor  (Read 1161 times)

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Offline 741Topic starter

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Analog tempco compensation for ZnO gas sensor
« on: January 09, 2020, 03:46:51 pm »
I'd like to remove the tempco from an MQ-2 sensor. Circuitry is all analog (op-amps), minimal complexity. Perfection is not needed. Attached are two plots
  • EPCOS Resistance/temperature characteristics
  • MQ-2 Rs/Ro
The plots have somewhat different axis, but I think show essentially the same thing; how resistance varies with temperature.

Looking at the EPCOS NTC B=2000 curve and the MQ2 33% RH curve, and ignoring the small difference in "baseline temperature" (25C at top, 20C at bottom) then it seems below 20C, the curves track well but above the MQ-2 curve is much flatter.

What I would like is that the NTC curve is simply some scaled, shifted version of the MQ2 curve, then I could believe it'd easy to implement compensation.


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