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Re: Oxygen Sensors used in EFI systems

Hi Michael, Murray, et al -
here is a linking to satellites, -
on P3E we could build in, as a one time only, battery
powered, smoke, gas, propellant leak detection device
that would send out a signal, when queried by command
stations, if detection had been positive, anywhere in SC.
Of course this unit would need to be totally independent
with own antenna, receiver, transmitter and generally
"bullet proof" packaging in NBC form.

73 Jens    ZL2TJT

"Michael P. Olbrisch" wrote:

> > -----Original Message-----
> > From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
> > Behalf Of Murray Peterson VK2KGM
> > Sent: Friday, February 16, 2001 8:09 AM
> > To: AMSAT-BB
> > Subject: [amsat-bb] Oxygen Sensors used in EFI systems
> >
> >
> > I know this is not exactly a satellite related subject but I
> > was wondering whether there is anyone on this list who
> > knows (from an electronic point of view) how an Oxygen
> > Sensor works. Is it a variable resistor of sorts? Do you
> > apply a constant current to it and measure the voltage
> > across it?
> Good morning Murray,
>         It depends on which model you have.  We use
> passive devices.
>         Although a bit away from automotive use, we use
> not only oxygen sensors, but other similar devices in the
> monitoring of pollution.  Here is how it is done.
>         The device has two thermisters in it.  One is a bare
> thermister.  The other is coated with a chemical that reacts
> to the presence of the pollutant we wish to monitor.
> (oxygen in your case)
>         The bare thermister acts as the reference, telling us
> the overall sample temperature.  The coated thermister
> shows a higher (or lower) temperature because of the
> presence of the pollutant.  By using known test samples,
> and developing a calibration curve, you can determine the
> level of pollution for a given output.
>         This is but one way, and a simplified way at that.
> I do not remember the coating chemicals in my head, nor
> the resistances of the thermisters, nor the temperature
> coefficients.  Heck, 0600 on a Friday morning, I would
> not remember my name, except that it is in the signature
> block below.
>         Hope it helps.
> Mike.
> My E-mail address: mailto:kd9kc@elp.rr.com
> Ham Radio page: http://www.qsl.net/kd9kc/
> Gun page: http://home.elp.rr.com/elpasochl/
> Self defense... you can own and carry a handgun to protect
> yourself, or dial  9 1 1  and maybe wait the rest of your life.
> ----
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