The sensor of the fuel level gauge is a cy lindrical capacitor
with inner electrode 1, outer electrode 2 and insulating layer 3.
Between in su latin g layer 3 and outer electrode 2 is a layer of
fluid (fuel) 4 whose level is to be controlled. When the level of
fluid 4 varies in the capacitor, the capacitance also varies because
the p e rm ittiv ity of the fluid and th at of air differ. V a ria tions
in the capacitance of the capacitor are registered by the
measuring instrument.
$4336$SmE,M$