temp gauge drop when termostat is opened

[Huw Powell]

> I thought that every gauge is to be calibrated to some standard signal (voltage from
> sensor, pressure,  etc.).  In case of temp sensors the output signal is voltage.

not the coolant gauge sender on our cars - it is a variable resistance
in series with a regulated voltage and the gauge coil.

>  Frankly speaking I do not know anything about
> types of temp sensors used in cars.   I am just curious how VDO, for example,  gauges are
> calibrated?  Or maybe all sensor are standard in car industry?

probably not calibrated too intensely, heck, they don't even have
numerical scales on them.  Just enough for "normal" to be in the middle
and "too hot" to be 3/4 scale or so.  But they did go to the trouble of
running the coolant temp gauge and fuel gauge from a voltage regulator
to isolate them from operating voltage vagaries at least.

-- 
Huw Powell

http://www.humanspeakers.com

http://www.humanthoughts.org