Date: Wed, 27 Mar 1996 08:35:49 -0800 (PST)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Rainer Heller <rainer@geophys.washington.edu>
Subject: Re: questions on temp gauges
There's also a phenomenon wit h a fancy name I forget right now,
works like this:
Put two metals together that need different energies to get rid of
one electron. Temperature dependence of the get-rid-of- the-electron
stuff leads to a voltage.
Think it was the Zeeman effect.
Don't know how realible and technically applicable that effect is.
My guess is that there should be some voltage supply and you have
some temperature dependent resistance.
Rainer
85 Vanagon
On Thu, 21 Mar 1996, Maher, Steve (SD-MS) wrote:
>
> >> option is to bolt it in with the #3 sparkplug. I feel bad about
> >> contradicting David Schwarze, but it's feasible: you only need to bend a
> >> right angle into the VDO CHT sensor.
> >
> >Been there, done that. Still didn't fit - not enough clearance. But it
> >it works for you, great! I don't know what's different on your engine,
> >but something has to be, cause there is NO WAY that sucker would fit
> >under _my_ spark plug. :)
> >
> >> The CHT gauge kit is, like, "self-powered." :-) The heat will generate
> >> tiny amounts of current in the sensor (forgot the term for this
> >> phenomenon)
> >
> >I believe it's "thermocouple".
>
> I thought a thermocouple was a variable-resistance device, that changed
> its resistance with temperature? You still have to "power" it from an
> outside source. Most gauges I've seen, such as the water temp gauge in
> the V6anagon, take in 12V from your ignition switch, route it thru the
> gauge, then out the other side, thru a LONG wire back to the sender on
> the engine, which varies its resistance as I mentioned. The gauge actually
> measures the amount of current that the sender lets flow through it to
> ground (the metal of the engine it's mounted on).
>
> Does the CHT gauge kit you mentioned, have NO connnection to any voltage
> source? Oops, then, *never mind*... perhaps a peizoelectric device of
> some kind? :^)
>
> ---------------------------------------------------------------------
> Steve Maher smaher@gi.com '80 V6anagon w/Chevy 2800
> '66 Mustang Coupevertible, for sale
>
> Check out the cars at http://www.lookup.com/homepages/76242/home.html
>
> *** What part of "Shall not be Infringed" don't you understand? ***
> ---------------------------------------------------------------------
>
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