Abstract: A load applied to a load cell's load-bearing member (21) causes that member to move against the force applied by springs (28 and 30) and thereby bring a magnet (24) into closer proximity to the ferromagnetic core (12) of a coil (10). Acting across a small gap, the magnet partially saturates a magnetic circuit that encloses the coil. This force-caused magnet motion changes the coil inductance and the magnetic circuit's degree of saturation. By applying to the coil (10) a brief voltage pulse without thereby heating it significantly, and by observing the coil current's resultant steady-state value and the rate at which the coil current approaches that value, an inductance-to-load converter (FIG. 4) calculates the applied load and the coil's temperature and generates outputs that represent them.

Abstract: Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A permanent magnet (42) mounted on the diaphragm (30) so moves with diaphragm flexure as to vary the magnetic saturation of a saturable circuit in which the coil (34) generates flux. By determining the coil's inductance under quiescent-diaphragm conditions, a computer (56) can infer the ambient pressure that bears upon the liquid (10). By compensating for the static pressure thus inferred, it can then determine liquid level by observing diaphragm oscillations reflected in coil electromotive force generated by the magnet (42) as the diaphram (30) undergoes oscillatory flexure in response to the coil's momentary excitation.

Abstract: Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A strain gauge (46) detects the diaphragm flexure, and analysis circuitry (62) determines the liquid level as a function of the resultant oscillation frequency and the diaphragm's static flexure.