Wide Ratio O2 Meter

[Steven Gorkowski]

Is this resistor a variable resistor with temp if so we can read O2 temp
and do temp compensation with the pic data logger I'm building.

Steve

garfield at pilgrimhouse.com wrote:

> On Tue, 10 Mar 1998 22:23:57 -0700, Land Shark <lndshrk at xmission.com>
> wrote:
>
> > Guys.. here's what I think..
> >
> > Take a look at the HONDA sensor for example..
> .....
> > Simple.. there is a CALIBRATION resistor that becomes part of the
> driver circuit
> > built into EACH one (in the plug)
> >
> > Note: Both the HONDA and Horiba/NTK sensors use SEVEN connections..
> >
> >       2 for heater
> >       3 for sensor
> >       2 for CAL RESISTOR!
> >
> >       The Cal resistor is inside the NTK SENSOR, but in the honda
> one, it is inside
> >        the sensor CONNECTOR!
> >
> > So, somewhere in that masterfully unknown op-amp rich circuit is a
> single calibration
> > resistor which is with the sensor itself
>
> Hmmm, now we're getting somewhere! I just looked at an NTK sensor, and
>
> sure enough, although the sensor wire bundle only has 5 wires, the
> connector DOES have 7 pins, just like Jim says, AND, you can see that
> those two extra pins are NOT connected to the others (I also measured
> to
> be sure), and that they terminate in a square plastic cavity that's
> molded into the connector. I just did a "Thevinin" test on those two
> terminals, they are NOT polarity sensitive, show no signs of
> capacitance, and read around 3K ohms.
>
> eXcellent factoid, Jim. Oooooh, this is gettin interestin.
>
> Garfield