Means for sensing change in the amount of fluent material in a reservoir

Abstract From the Canadian patent

A fluid level sensor comprising a novel electronic circuit which monitors change in the fluid level in a reservoir through a conductive probe disposed therein. The probe and a capacitor are electrically connected in a circuit which is intermittently energized to create an electrical transient therein The transient is monitored, and a warning is given when the transient indicates that the probe is not in contact with the fluid in the reservoir. Two species of the invention are disclose as applied to a vehicle hydraulic brake system having a dual reservoir type master brake cylinder with a probe for each reservoir. In one species, only a single capacitor is required since the electronic …