A moisture absorbing sensor is provided that includes a hygroscopic material that maintains a shape before and after moisture absorption and maintains a hygroscopic state for a predetermined time or more after moisture absorption; and an electrode disposed in the hygroscopic material. Moreover, an electrical characteristic of a circuit formed by the electrode and the hygroscopic material changes according to a moisture absorption amount of the hygroscopic material.

Embodiments disclosed herein comprise a sensor. In an embodiment, the sensor comprises a substrate having a first surface and a second surface opposite from the first surface. In an embodiment, the sensor further comprises a first electrode over the first surface of the substrate, and a second electrode over the first surface of the substrate and adjacent to the first electrode. In an embodiment, the sensor further comprises a barrier layer over the first electrode and the second electrode.

Apparatus for measuring at least one property of a fluid comprises a capacitive fluid sensor (110) comprising a first electrode (111) and a second electrode (112) with a sensing region (113) between the electrodes. The apparatus comprises an alternating signal source (120) configured to apply an alternating drive signal to the capacitive fluid sensor (110). The apparatus comprises a processing apparatus (200) configured to receive a sense signal from the capacitive fluid sensor (110) and the alternating drive signal. The processing apparatus (200) is configured to: determine a complex difference signal comprising an in-phase difference component between the drive signal and the sense signal and a quadrature difference component between the drive signal and the sense signal; determine the at least one property of the fluid based on both the in-phase phase difference component and the quadrature difference component of the difference signal.

A system for imaging material, typically in an underground scenario, comprising of a plurality of conductive electrodes supported on a conductive substrate positionable in an environment to be imaged, a signal generator connected to at least two of the electrodes, and a signal detector connected to at least two of the electrodes, and wherein an impedance compensator is arranged between each electrode and its substrate to counter parasitic impedance between the two. Typically the impedance compensator may be arranged to act as a negative capacitance, which may be approximately equal to any capacitance between the electrode and the substrate. An electrode may be a drive electrode coupled to a signal generator, or a detector electrode coupled to a detector, or may be reconfigurable to act as either one.

A sensing device includes at least one vibration sensor that responds to sensed vibrations. At least one drive-sense circuit is coupled to the vibration sensor, wherein the at least one drive-sense circuit includes: a first conversion circuit configured to convert a receive signal component of a sensor signal corresponding to the at least one vibration sensor into the sensed signal, wherein the sensed signal indicates a change in an electrical characteristic associated with the at least one vibration sensor; and a second conversion circuit configured to generate, based on the sensed signal, a drive signal component of the sensor signal corresponding to the at least one vibration sensor.

Capacitive sensors and capacitive sensing data integration for plasma chamber condition monitoring are described. In an example, a plasma chamber monitoring system includes a plurality of capacitive sensors, a capacitance digital converter, and an applied process server coupled to the capacitance digital converter, the applied process server including a system software. The capacitance digital converter includes an isolation interface coupled to the plurality of capacitive sensors, a power supply coupled to the isolation interface, a field-programmable gate-array firmware coupled to the isolation interface, and an application-specific integrated circuit coupled to the field-programmable gate-array firmware.

Provided is an electrical circuit for electrochemical measurement of a solution, said electrical circuit comprising: a voltage generation circuit; an operational amplifier that has an output (OUT), a non-inverting input (+IN), and an inverting input (−IN), wherein the output (OUT) is connected to a counter electrode (CE) in contact with the solution, the inverting input (−IN) is connected to a reference electrode (RE) in contact with the solution, and the non-inverting input (+IN) is connected to the voltage generation circuit; a capacitor that is connected between the output (OUT) and inverting input (−IN) and has a capacitance of 1 μF or greater; and a current measurement circuit that is connected to a working electrode (WE) in contact with the solution.

A sensor for measuring ocean water salinity is described. The sensor may include a measurement clock circuit, a control clock circuit, and a comparator circuit. The measurement clock circuit, having an output that varies with salinity of a fluid, may have a first circuit architecture that includes a capacitive gap assembly that permits a fluid to flow into a gap between two electrodes of the capacitive gap assembly. The control clock circuit, having an output that does not vary with salinity of the fluid, may have a second circuit architecture comprising a capacitor. The comparator circuit may be configured to compare the controlled clock output to the measured clock output over a duration of time to determine a salinity measurement of the fluid. The first circuit architecture may differ from the second circuit architecture in that an electrically connected position of the capacitive gap assembly within the first circuit architecture is the electrically connected position of the capacitor within the second circuit architecture.

The invention relates to a sensor device and a method for detecting properties of a liquid. The liquid is accommodated in an inner chamber 14. A capacitor arrangement 22, 26 in the inner chamber has spaced, opposing capacitor surfaces 24a, 24b, 28a, 28b so that at least part of the liquid accommodated in the inner chamber 14 is arranged between the capacitor surfaces 24a, 24b, 28a, 28b. An evaluation device 30 for supplying an output signal A depending on a capacitance value C1, C2 of the capacitor arrangement 22, 24 comprises an excitation circuit 32 and an evaluation circuit 34. The excitation circuit 32 has at least one measuring resistor R1, R2, R1a, R1b and means for applying an AC voltage to a series circuit consisting of the measurement resistor R1, R2, R1a, R1b and the capacitor arrangement 22, 24. The evaluation circuit 30 has means for supplying the output signal A by measuring a voltage U1, U2 across the capacitor arrangement 22, 24.

Methods and systems for monitoring fluid levels and electrolyte levels used in a dialysis machine. A receptacle, configured to receive a container, comprises a plurality of curved side panels and a base to form a cylindrical shaped cavity for receiving a container. Each panel includes a conductive material on its inner surface and, optionally, a shielding on its outer surface. An electronics component housed within, or near, the receptacle drives the capacitive process and interprets generated data to determine fluid levels and compositions. An alternate receptacle includes one or two coils wrapped about the container and uses induction to determine fluid level.