GM used a dual coil indicator instead of the mechanical voltage regulator. One coil is across the 12 volt supply, while the other coil is in series with the sending unit. I may have the schematic and some line drawings in an old GMC truck manual.
-- ? Michael A. Terrell Central Florida
not only do you need a digital pot with low resistance you need one that can handle voltages outside of its supply voltage...
it may be easier to use a PWM output and some sort of smoothing network.. it really deppends on how the digital console reads the fuel level sender...
If as i suspect is times a capacitor discharging through it you'd probably do best with something like this
+--- to fuel gague | +5v ---|-- Bye. Jasen
Neat, I didn't think of that. One coil tracks the battery voltage and varies the field accordingly. elegant.
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both coils are attached to the needle. there's also a permanent magnet produucing the field.
by doing it that way they didn't need to regulate the supply voltage as the ratio of current between the two coils remains constant so the needl keeps pointing the same direction with 8 of 15V.
Yeah, I've seen those.
I had the thing apart, (when I replaced the instrument cluster)
it looked pretty mmuch like a standard moving coil meter (like the voltmeter one) except there were two coils at 90 degree angles and two hairsprings at one end to suupply the two coils.
It may be a european thing, this car was Russian ('91 Lada samara) and english '54? Morris Minor used a similar setup AFAICT, with that one the sender had a dead spot near empty and when it hit it the needle went wild. and bounced off the stop which was wearing a notch in the side of the needle.
Bye. Jasen
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