Patent ID: 8291761
Filing Date: 2012-10-23
Classification: F04B,F04D,G01F,H05K,Y10T

Abstract:
1. A method of manufacturing a solid state fluid level sensor for activating a pump, comprising the steps of: disposing a first electrode and a second electrode on a dielectric substrate; disposing a current switching device and a first differential sensing circuit on the dielectric substrate; electrically coupling the first and second electrodes to the current switching device and the differential sensing circuit to form a printed wiring board assembly, the first and second electrodes being configured to apply common mode signals to inputs of the first differential sensing circuit; providing a housing that forms a fluid-proof cavity that is adapted to be submerged in a fluid whose level is to be detected; disposing the printed wiring board assembly in the housing; and sealing the printed wiring board assembly within the housing.