The probe of a capacitance-type fuel level gauge primarily functions as what type of component?

The probe of a capacitance-type fuel level gauge functions as a capacitor, with the fuel and the air above it acting as the dielectric material. In this type of system, the capacitance is affected by the level of the fuel within the tank because the dielectric constant of fuel differs from that of air. As the fuel level changes, the effective area and the dielectric properties of the capacitor change, which in turn alters the capacitance value. This change in capacitance is used to indicate the fuel level.

This principle is why option B is the correct answer; it captures the essential operational aspect of the capacitance-type fuel level gauge. The relationship between the dielectric materials (in this case, fuel and air) and capacitance is fundamental for accurately measuring the fuel level in an aircraft’s fuel system.