Abstract: The output of a capacitance fuel sensor is supplied to two switches that are controlled by a switching control unit. The two switches are opened and closed in synchronism and antiphase with one another, and in quadrature with the drive voltage applied to the sensor. The output of one switch is supplied to the input of a first integrating current-to-voltage amplifier which in turn supplies a signal representative of fuel quantity to a fuel indicator. The output of the other switch is supplied to another integrating current-to-voltage amplifier which in turn supplies a signal representative of the quantity of contaminants to a contaminant indicator.

Abstract: A capacitive fluid-gauging probe has a tubular electrode that is secured at its upper end to the wall of a reservoir by an integral mount moulded from a frangible plastics material. The mount has a collar that is fitted to the probe and from which extend radially three pairs of struts. The struts are joined at their outer ends with respective pillars that extend parallel to the probe. The pillars are joined with a plate that is secured to the wall of the reservoir above the probe. Domed plugs are inserted in both ends of the electrode to protect the wall of the reservoir which may be of flexible material. Preferably the ends of the probe are spaced from the reservoir walls. In operation, excessive force on the probe causes the struts to break, thereby allowing the probe to be displaced within the reservoir.

Abstract: A connector assembly for a capacitive fuel-gauging probe comprises a socket assembly, mounted on the probe, and plugs. The socket assembly has several sockets each of which has an elongate contact element. The inner surface of each socket has a number of axial rails and channels which engage with rails and channels formed on the outer surface of the housing of a cooperating plug. The cooperating surfaces of the plugs and sockets differ one from the other so that only the correct plug can be inserted in the correct socket. The contact element of each plug is in the form of a resilient loop, the upper portion of which has a projection that locks with an aperture in the socket contact element. Pulling the plug housing out of the socket moves the projection out of the aperture so that the plug can be withdrawn.