Wide Ratio O2 meter

[garfield at pilgrimhouse.com]

On Thu, 12 Mar 1998 14:58:34 +0000, steve ravet
<steve at sun4c409.imes.com> wrote:

>A post from a long time ago claimed that the ion pump is a second sensor
>mounted next the the first.  The work both ways, not only does a
>difference in oxygen partial pressure create a voltage, imposing a
>voltage pumps oxygen from one side to the other.
>
>So they're basically two EGO sensors back to back, the second one is
>driven to maintain the first at some fixed voltage, the current required
>indicates the amount of oxygen.

Huh, that sounds almost understandable. And bloody clever, too!

It may also help to understand how the ND thingee that Charles mentioned
earlier can have a sensor you both sense AND pump, using the same wire
pair. Curious how they can get away with putting two O2 sensors
back-to-back, have one as the sensor and one as the pump, and still only
need two terminals on theirs, instead of the 3 the NTK needs? Hmmm, one
mystery solved, and just like oneOthem whackamoles, up pops another.
Interwesting, vewy interwesting. Time to hit the books, I guess.

Garfield