In an electronic-type fuel quantity indicating system, what is the tank sensing unit?

In an electronic-type fuel quantity indicating system, the tank sensing unit functions as a key component in measuring the fuel level. Specifically, it typically uses a capacitor to measure the capacitance, which changes with the amount of fuel in the tank.

The operation relies on the principle that the dielectric constant of the fuel differs from that of air. As the fuel level changes, the dielectric environment between the plates of the capacitor changes, resulting in a change in capacitance. This change is then converted into an electrical signal that corresponds to the fuel level, allowing the system to accurately indicate how much fuel is present.

The other options, while they are components used in electronic circuits, do not serve this specific purpose within the fuel quantity indicating system. For example, a sensor could refer to many different types of sensing mechanisms, but in this context, it’s not specific enough to describe the function of measuring fuel quantity. Similarly, a condenser is often associated with energy storage in circuits, and a resistor is used to limit current flow, neither of which directly measures fuel level changes in this type of system. Thus, the capacitor is the correct choice as it directly relates to the tank sensing unit used for quantifying fuel in the electronic fuel quantity system.