Abstract: Systems and methods for detecting and monitoring areas of water damage or water management problems in a property are described. Monitoring devices can be deployed at different locations of a property to obtain sensor data and image data regarding the environmental conditions in potentially problematic areas of the property. An image obtained by the monitoring devices can be processed and compared with reference images or other image data that is filtered in a different manner that the image to identify portions of the image in which water damage or water management problems exist.

Abstract: A distribution transformer monitor includes a housing arranged for positioning in proximity to a distribution transformer vessel. The monitor also includes a sensor arranged in the housing, which is positioned to generate digital data associated with at least one environmental condition that exists inside the distribution transformer vessel, and a processing circuit arranged to determine from the generated digital data that the at least one environmental condition has crossed a threshold. The sensor may include any one or more of a temperature sensor, a camera, an accelerometer, a pressure sensor, and a microphone. The housing of the distribution transformer monitor may include at least one indicator legend arranged to facilitate positioning of the housing in a substantially vertical orientation relative to the distribution transformer vessel.

Abstract: The liquid level meter according to the present invention includes a resistive temperature detector, a temperature measuring body located above it, a temperature detecting unit detecting temperatures of the resistive temperature detector and the temperature measuring body, a current controlling unit determining a current value to be flowed through the resistive temperature detector so that the resistive temperature detector and the temperature measuring body become a predetermined temperature difference, a power supply unit supplying the current of the determined current value to the resistive temperature detector, and a liquid level detecting unit detecting a position of a liquid level.

Abstract: A heating, ventilation, and air conditioning (HVAC) system includes an expansion device disposed between a condenser and an evaporator of a vapor compression system and a control panel communicatively coupled to the expansion device. The control panel is configured to: determine a liquid refrigerant level set point of the condenser based on parameters of the vapor compression system, provide a first control signal to increase an opening of the expansion device in response determining that the current liquid refrigerant level in the condenser is greater than a determined liquid refrigerant level set point of the condenser, and provide a second control signal to decrease the opening of the expansion device in response to determining that the current liquid refrigerant level in the condenser is less than the determined liquid refrigerant level set point of the condenser.

Abstract: A method of forming a fluid level sensor includes coupling an array of heating elements and sensors to a first side of a substrate. A second side of the substrate is coupled to a carrier. The method also includes coupling an electrical interface to the carrier and electrically coupling the array to the electrical interface via a conductive wire. The method further includes overmolding the electrical interface, the first side of the substrate, and the conductive wire to form an overmolded fluid level sensor. The carrier may be coupled to the second side of the substrate and the electrical interface via a releasable adhesive and may be removed after overmolding the fluid level sensor.

Abstract: An interposer for vertically separating device die is disclosed. The interposer includes a compliant layer comprising a plurality of thermally conductive plugs that are physically disconnected within the plane of the compliant layer, where the space between the plugs is filled with a compliant medium. In some embodiments, at least one of the top and bottom surfaces of the compliant layer is coated with a thin layer of electrically insulating material.

Abstract: A liquid level meter includes a first resistive temperature detector; a first temperature measuring body a liquid level detection section a temperature detection section detecting the temperatures of the first resistive temperature detector and the first temperature measuring body; a current control section determining a value of a current to apply to the first resistive temperature detector such that a difference between the temperatures of the first resistive temperature detector and the first temperature measuring body detected by the temperature detection section to be a first constant value; and a power supply unit supplying a current of the determined current value to the first resistive temperature detector; wherein the liquid level detection section determines whether the first resistive temperature detector is present in a liquid or outside of the liquid using the value of the current applied to the first resistive temperature detector.

Abstract: A refrigeration cycle apparatus includes a refrigeration cycle in which refrigerant circulates, the refrigeration cycle including a compressor, an outdoor heat exchanger, expansion valves, and indoor heat exchangers, which are connected to each other via a refrigerant pipe, a heat source unit accommodating the outdoor heat exchanger, use-side units accommodating the indoor heat exchangers, and a control unit that controls at least turning on and off of the refrigeration cycle. The control unit detects abnormality of the refrigeration cycle based on the pressure or temperature of the refrigeration cycle in an off time of the refrigeration cycle.

Abstract: A reactor state monitoring apparatus including: a first gamma ray-dose measurement device that detects and measures an atmospheric radiation dose caused by radioactive substances on a containment vessel side respective to a biological shielding wall surrounding a pressure vessel and outside the pressure vessel; a second gamma ray-dose measurement device that detects and measures a radiation dose on the pressure vessel side respective to the biological shielding wall; a fuel radiation measuring device that detects and measures a radiation dose of fuel in the pressure vessel; and a water amount evaluation device that calculates a difference between radiation doses measured by the fuel radiation measuring device and the first gamma ray-dose measurement device as a corrected fuel radiation dose, and acquires a cooling water level as a water level evaluation value, based on the radiation dose measured by the second gamma ray-dose measurement device and the corrected fuel radiation dose.

Abstract: A crankcase heating control system for a heat pump system includes a data receiving module and a power control module. The data receiving module receives data indicative of a temperature of a compressor of the heat pump system, data indicative of an ambient temperature, and data indicative of a current date and a current time. The power control module selectively applies power to a heater of a crankcase of the compressor and selectively disables the heater based on the temperature of the compressor, the ambient temperature, the current date, and the current time.

Abstract: The present invention relates to a method of controlling an icemaker for a refrigerator, and more particularly to a method of controlling an icemaker for a refrigerator which can automatically determine a water shortage situation during water supplying, ice making, and ice separating processes of the icemaker, can prevent production of imperfect ice pieces, and can solve an ice separating defect, thereby smoothly performing an operation of the icemaker.

Abstract: A two-wire process variable indicator includes a housing having a plurality of terminals disposed therein. The terminals are coupleable to a two-wire process control loop. A power module is coupled to the plurality of terminals to receive current flow from the process control loop. Driver circuitry is coupled to the power module and a microencapsulated electrophoretic display is coupled to the driver circuitry.

Abstract: A PTC composition comprises crystalline polymer and conductive ceramic filler dispersed therein. The crystalline polymer has a melting point less than 90° C. and comprises 5%-30% by weight of the PTC composition. The crystalline polymer comprises ethylene, vinyl copolymer or the mixture thereof. The vinyl copolymer comprises at least one of the functional group selected from the group consisting of ester, ether, organic acid, anhydride, imide or amide. The conductive ceramic filler comprises a resistivity less than 500 ??-cm and comprises 70%-95% by weight of the PTC composition. The PTC composition has a resistivity about 0.01-5 ?-cm and its resistance at 85° C. is about 103 to 108 times that at 25° C.

Abstract: This asphalt loading arm is for dispensing fluids from a storage tank to a receiving tank. The loading arm includes an overfill probe to prevent overfilling during transfer from one tank in loading lanes at asphalt terminals. The overfill probe is a rapid temperature response probe. The rapid response temperature probe that has a very fast response time. Placing a transmitter on the probe uniquely allows a PLC to collect data from the probe.

Abstract: A pencil-shaped electrical heating element, in particular for application in a device for measuring filling level in a liquid container, in particular in a reactor chamber of a nuclear plant, contains an electrically-conducting sleeve and at least one electric line embedded therein which is in conducting contact with the sleeve. The electrical line has at least two line sections with differing electrical properties and/or thermal conductivities.

Abstract: The performance of a PCA unit associated with an airport gate is monitored by a temperature sensor in the stream of output air leaving the PCA unit, to produce a signal indicative of the temperature of the output air that may be compared to an acceptable range of values, or to the temperature of air input to the PCA unit (as measured by a second temperature sensor). An alert is generated to a human operator if the temperature measured does not compare favorably with the desired range.

Abstract: A method and system for steam leak detection. The method comprises obtaining real-time temperature data representing a heat dissipation of a steam pipe along a steam pipe route, processing the real-time temperature data in real-time to determine at least one indication of a potential steam leak based on the real-time temperature data and to generate a processed image for display, and displaying the processed image to depict the heat dissipation of the steam pipe.

Abstract: A system for monitoring the fermentation process in connection with ensilage of fodder (1) comprises a sensor device (3) arranged in the fodder during the ensilage thereof and a monitoring device (11) operatively connected to the sensor device during the ensilage. The sensor device (3) comprises at least one sensor (3a-c) provided for repeatedly measuring the content of at least one chemical substance in the fodder, which is affected by the fermentation process. The monitoring device comprises receiving means (12) provided for receiving the repeatedly measured values of the content of the chemical substance; processing means (13) provided for comparing the repeatedly measured values with reference values of the content of the chemical substance; and notifying means (14-16) provided for notifying a farmer (17) depending on the outcome of the comparison of the repeatedly measured values and the reference values.

Abstract: Described are a method and a sensor aware network for dynamic processing of sensor data. Network context data are inserted into data packets from sensors or local sensor networks coupled to the sensor aware network. Sensor aware nodes in the sensor aware network can read the context data and can respond by performing specific network actions. The sensor data and network context data are provided to one or more application nodes. The sensor data and network context data can be stored in a database and later searched according to the network context data. Advantageously, sensor data flows can be treated differently by the sensor aware network, the application and the user, depending on the type of sensor data and the actual data values. Thus critical responses to certain sensor data flows can be implemented more efficiently than otherwise possible using conventional network configurations.

Abstract: An overfill probe is utilized in each compartment of a multi-compartment transport tanker and has a depending sensing tube for detecting liquid overfill conditions. An overfill detector is within the bottom end of the probe tube and is thus protected from damage. Internal damage to the probe and malfunction of the system also precluded by connecting the exposed cap of the probe to the detector by a longitudinally extensible, stretchable cable extending through the tube to the detector, or a circuit board may be retained within the depending tube. Additionally, a thermistor socket and an optic socket are provided which are part of the overfill protection system, each having contact connections that may be readily replaced when worn without removing or replacing the wiring within the socket assembly.

Abstract: A fluid level sensor and drain fitting is provided that includes a fitting body having a first annular end, a second external-threaded end with an opening therein, and a passage extending from the opening to the first annular end. The drain fitting further includes a plurality of sensors forming an array on the second external-threaded end radially spaced around the opening such that at least one sensor is above the centerline of the opening regardless of the rotational position of the fitting. Each of the sensors are configured to provide an output that changes in response to contact with water. The plurality of sensors are configured to detect a water level relative to the opening in the fitting body based on the number of sensors in the array that provide an output indicative of contact with water.

Abstract: A communication terminal includes a first wireless communication unit that communicates with a base station; a second wireless communication unit that communicates with another communication terminal including an equivalent of the first wireless communication unit; a temperature measurement unit; and a control unit that selects one of the first wireless communication unit and the second wireless communication unit according to a temperature measured by the a temperature measurement unit.

Abstract: A modular device for determining attributes of a substance stored in a container having a sensing module, a transmitter module and a power source module. The sensing module is capable of sensing attributes of a substance and providing an output. The transmitter module is configured to transmit an output of the at least one sensing module when operably coupled to the sensing module. The power source module is capable of being operably connected to the sensor module and the transmitter module to power the sensor module and the transmitter module.

Abstract: A system includes a controller configured to receive a signal from a thermal radiation sensor indicative of a temperature of a region including at least one fluid passage. The controller is also configured to detect a leak within the at least one fluid passage based on the signal.

Abstract: A wastewater holding tank sensor probe for use in determining the presence of a conductive liquid held within a wastewater holding tank in a recreational vehicle is disclosed. The probe is less sensitive to the presence of conductive residue as a result of an improved geometry and/or choice of materials that reduce the leakage currents between the probe tip and the sensor probe attachment surface, typically the wall of the tank. This reduction in sensitivity to conductive residue buildup can be measured by a geometrically determined resistivity factor between the probe tip and the mounting surface of the probe. The reduction in sensitivity can also be measured by the length of the path through the conductive residue between the probe tip and the mounting surface of the probe. A variety of geometries and material choices to reduce the sensitivity of electrical conductance based sensor probes to conductive residue are disclosed.

Abstract: System for monitoring oil level and detecting leaks in power transformers, reactors, current and potential transformers, high voltage bushings and the like, notably for a system that through the use of sensors and other electronic components measures and monitors transformers and similar equipment in real time, filled with insulating oil, with greater precision and without need for floats or mobile mechanical parts, while presenting countless facilities in the sense of making level monitoring more reliable and safer, highlighting the level error calculations, oil leak detection alarm, excess oil detection alarm during the equipment filling process and calculation of tendencies of evolution for levels among other facilities.

Abstract: In a method and system for monitoring the power state of an x-ray emitter and/or an x-ray detector, the x-ray emitter is operated according to a set of test parameters, so as to emit x-rays that strike at least a portion of the detector region of the x-ray detector. At least one value characterizing the operation of the x-ray emitter and/or the x-ray detector is determined, and this detected parameter is compared with a comparable reference parameter value. The power state of the x-ray emitter and/or the x-ray detector is determined based on deviation of the detected parameter from the reference parameter.

Abstract: A dispensing urn assembly (10, 10?) with a hollow body (12) with an interior surface for containing beverage (14) and a manually operable faucet (16) for selectively dispensing beverage (14) from the bottom of hollow body with an electronic status display assembly (50) controlled by a microcomputer (62) in response to a temperature probe (44), a level probe (42) and a timer reset switch (46) to provide graphic displays (64,68, 72), numerical displays (66,70, 74) of the temperature, quantity and time elapsed or remaining since the brewing of the beverage and light indication displays (55,57, 59) when preselected values are achieved.

Abstract: System for monitoring oil level and detecting leaks in power transformers, reactors, current and potential transformers, high voltage bushings and the like, notably for a system that through the use of sensors and other electronic components measures and monitors transformers and similar equipment in real time, filled with insulating oil, with greater precision and without need for floats or mobile mechanical parts, while presenting countless facilities in the sense of making level monitoring more reliable and safer, highlighting the level error calculations, oil leak detection alarm, excess oil detection alarm during the equipment filling process and calculation of tendencies of evolution for levels among other facilities.

Abstract: This heat pump type hot water supply apparatus has a remaining hot water display (41) which displays remaining hot water in a hot water storage tank (22) by a plurality of scales (41a-41e) step by step, and a display controller (30) which changes the remaining hot water display (41) according to the amount of remaining hot water in the hot water storage tank (22). A change amount of hot water which changes a level lighting 3 scales (41c-41e) of the remaining hot water display (41) to the next level thereof by the display controller (30) is larger than a change amount of hot water which changes a level lighting 4 scales (41b-41e) of the remaining hot water display (41) to the next level thereof by the display controller (30).

Abstract: A system comprising at least one liquid detector that has a cathode and an anode and at least one switching mechanism for receiving a positive voltage from the cathode and anode of a liquid detector. Each switching mechanism comprises at least one switching component that is connected with a power source. Each switching component supplying a current from its connected power source when the switching component is activated. Preferably, each switching component is activated, when the switching component receives a voltage that exceeds a threshold voltage. The system also comprises a base unit that communicates remotely or through direct connection with each switching mechanism. The base unit communicates with at least one application control device that is connected with at least one electronic control apparatus for preventing the undesirable condition.

Abstract: A system for detecting water leaks is described. In one embodiment, the system includes a plurality of sensors, selected from a moisture sensor, a water level sensor, and/or a water temperature sensor. A processor collects moisture readings from the sensors. In one embodiment, the processor reports a possible water leak when a moisture sensor detects moisture above a moisture threshold value. In one embodiment, the processor reports a water leak when the water level reading exceeds a water threshold value and/or when the temperature reading exceeds a temperature threshold value.

Abstract: A sensing device arrangement for a fuel storage system is provided having at least one storage tank, a plurality of sensing devices positioned in or around the at least one storage tank, and a controller in electrical communication with the plurality of sensing devices. The controller is configured to communicate with each sensing device of the plurality of sensing devices on a single bi-directional data line. A sensing device of the plurality of sensing devices is activated by the controller. Data is acquired by the sensing device and transmitted to the controller over the data line. The controller instructs the sensing device to change to a low power state. The controller receives electrical characteristics from the plurality of sensing devices recognized on the data line and calculates a characteristic of the sensing device arrangement. The controller verifies compliance with an intrinsic safety barrier.

Abstract: A process for monitoring a fluid storage system using a vessel for storing the fluid and a detection apparatus using synchronized sensors for monitoring and measuring state properties of the fluid is disclosed. The method includes using a housing with at least one pressure sensor and at least one temperature sensor for synchronously collecting data regarding the fluid. Each sensor communicates with a processor and a signaling means to provide synchronized data. The method includes continuously forming at least one calculated value, such as a value for mass of the fluid, from the data synchronously collected using a processor, and continuously comparing the calculated value to at least one predetermined range of values for the fluid in the vessel to identify if the at least one calculated value is within the predetermined range of values. Then, the method includes communicating the compared values from the processor to an auxiliary device.

Abstract: A technique for quickly determining the type of liquid in a container externally regardless of the material of the container, preferably contactlessly. A halogen heater 102 and an infrared thermopile 103 are disposed outside an electrically conductive container 101 made of aluminum, for example. The surface temperature of the container 101 is measured when the halogen heater 102 is off, followed by the turning-on of the halogen heater 102 for two seconds, for example. The surface temperature of the container 101 is then measured, and a difference from the previous result of measurement is calculated. If the difference is smaller than a threshold value, the liquid in the container is determined to be a safe liquid consisting primarily of water, and a blue lamp is activated. If the difference is greater than the threshold value, the liquid in the container cannot be determined to be a safe liquid consisting primarily of water, and a red lamp is activated, indicating abnormality.

Abstract: Method of monitoring water conservation in an apartment complex by positioning infrared cameras with motion sensors in the clean outs of the waste water discharge lines leading to public sewer systems wherein each camera image is displayed on a computer screen and the motion sensors, which start and stop the digital video recorders (DVR), are adjusted by circumscribing the area of the camera image and the pixel sensitivity setting for motion sensors activation, which triggers the DVR recordings. In this arrangement the intermittent or constant flow of waste water is detected in real time indicating normal or abnormal flow of waste water, respectively. Further, an infrared camera may be positioned on the apartment complex side of the water meter to determine in real time if water is being supplied to the complex and the waste water flow out is little or none then loss of water outside the plumbing system from overflowing commodes, tubs, lavatories or broken pipe is indicated.

Abstract: Upon detection of a flammable gas condition, an intelligent thermostat regulates operation of appliances that have sources of ignition which could be the source of or may ignite the flammable gas. This hazardous condition is detected by a flammable gas detector and is communicated to the intelligent thermostat by wired or wireless communications. The intelligent thermostat then communicates with these appliances either via wired or wireless communications. The intelligent thermostat may also provide a visual warning user interface screen to inform the occupant of the hazardous condition, and may signal smoke detectors in the dwelling to sound an audible flammable gas warning. Alternatively, the flammable gas detector may signal the smoke detectors in the dwelling to sound an audible flammable gas warning directly.

Abstract: An improved liquid level sensor is disclosed which provides a reliable and simple device for accurately determining the level of a liquid within a vessel. The sensor utilizes a plurality of thermocouple junctions grouped in pairs with the pairs being spaced along a line extending generally in the direction in which the liquid level may vary. A first thermocouple junction of each pair is located in relatively close thermal proximity to an electrically powered heater and the second of each pair of thermocouple junctions is spaced away from the heater. The thermocouple junctions are connected in series and produce a signal indicative of the level of liquid along the sensor. Alternatively, a single threshold liquid level sensor is provided for use with a hermetic interface to provide a signal to indicate a level of liquid within a container. Additionally, a pressure sensing circuit may also be incorporated with either liquid level sensor.

Abstract: A level detector for storage tanks for fluids comprises a microprocessor, a network of resistive elements connected in series or parallel, and a plurality of conductive elements between them, connected across a power source. The resistive elements have a high temperature coefficient, and are heated by passing a high electric current through them, after which a low electric current is passed through them and the voltage between them is sampled by the microprocessor. The resistive elements lose heat through conduction, so that a pair of resistive elements can be detected having differential cooling between them as a consequence of being adjacent to the void within the tank or the fluid within the tank. Thus, an approximation of the fluid level within the storage tank can be determined and signalled remotely.

Abstract: The liquid level detector system of the present invention comprises a heater thermally coupled to the interior of the vessel. A linear sensor, having a vertical longitudinal axis, is located in proximity to the heater such that discrete elevations of the interior of the vessel are thermally coupled to corresponding longitudinal portions of the sensor. The correspondence is incrementally continuous such that the elevations corresponding to the portions of the sensor increase from one to the other end of the sensor. The sensor may be actuated resulting in a resistance measurement indicative of the temperature detected by it. The vertical dimension of the sensor is sufficiently large such that the resistance measurement will vary in proportion to the longitudinal portion of the sensor thermally coupled to the liquid. The sensor generates an electrical signal defining a temperature signal indicative of the resistance measurement and thereby the temperature detected by the sensor.

Abstract: An apparatus operable in a wet environment for detecting the presence or absence of water in a non-conductive vessel, by measuring changes in dielectric constant and detecting the temperature of water in same vessel. A conductive element coupled to a sensing and switching means, transmits data to the controller, resulting from a change of dielectric constant at the conductive element. A temperature sensor detects and transmits temperature signals to the controller. A controller means receives data, from the dielectric constant sensor means and temperature data from the temperature sensor. Includes a coupling means which transmits data from the controller to an external device. The isolation means electrically isolates the conductive element and temperature sensor means from the water contained in a non-conductive vessel.

Abstract: The invention relates to a method and device for the early detection of fire and for fighting fire indoors and outdoors, especially in living areas, of homes and buildings. According to the invention, a central freely programmable domestic control block comprising an intelligent bus system, sensors, and actuators controls, regulates and monitors the domestic technical system and, at the same time, sensors detect the direct and indirect fire characteristics, which are monitored by a separate check, control and regulating block that activates an extinguishing agent supply system when a set value has been exceeded. The aim of the invention is to improve a method and device of the aforementioned type such that the extinguishing agent is variably and selectively discharged with a high degree of efficacy by the provision of a system which can be modularly integrated in the security design of a building.

Abstract: A dispensing urn assembly (10, 10′) with a hollow body (12) with an interior surface for containing beverage (14) and a manually operable faucet (16) for selectively dispensing beverage (14) from the bottom of hollow body with an electronic status display assembly (50) controlled by a microcomputer (62) in response to a temperature probe (44), a level probe (42) and a timer reset switch (46) to provide graphic displays (64,68, 72), numerical displays (66,70, 74) of the temperature, quantity and time elapsed or remaining since the brewing of the beverage and light indication displays (55,57, 59) when preselected values are ahieved.

Abstract: A system for detecting the level of a liquid in a vessel, comprises a detector assembly including a thermally conductive substrate supported within the vessel. One or more heaters are mounted on the substrate within the vessel. One or more temperature sensors, each associated with a respective heater, are mounted on the substrate. The sensor(s) may be actuated to generate an electrical signal defining a temperature signal indicative of the detected temperature. A processor is electrically connected to the sensor(s) for receiving the temperature signal(s) after actuation of the associated heater(s). The processor is programmed to calculate a “temperature index” proportional to the temperature signal(s). The temperature index(s) indicates the temperature increase detected by the sensor(s) resulting from actuation of the heater(s). This, in turn, indicates the presence of liquid or vapor adjacent to the sensor(s).

Abstract: The invention relates to an indicator system for fluid levels, including two or more optically and/or thermally conducting fibers, preferably suitable for indicating the fluid level of a lubricant in the case of piston internal combustion engines. In this case, the fibers are either provided at the end with a substance varying in optical properties under the action of heat, or contain chambers which are filled with an appropriate substance.

Abstract: A limit-level sensor for measuring level of a liquid has a resistance element which has an electric resistance which suddenly varies a transition temperature which lies above the maximum liquid temperature. The resistance element is first of all heated by electric current. Thereupon, the electric resistance of the resistance element is measured. When the resistance element is covered with liquid, the heat generated by the electric current is led away so that the temperature of the resistance element is less than its transition temperature. If the resistance element is not covered by liquid, this heat is scarcely led away, so that the temperature of the resistance element remains above the transition temperature.

Abstract: A system for detecting the level of fluid in a fluid containing vessel. The system includes a device for applying energy to a selected location on the vessel. A sensor in proximity to the location detects the energy level at the location during first and second intervals. A memory device stores data representative of the energy detected by the sensor at each interval, and a logic circuit compares the amount of energy of the first interval to that of the second. Data corresponding to the level of fluid in the vessel may be displayed locally or signaled to remote data receiving and display devices, as appropriate.

Abstract: A sensing and measuring circuit, employing a positive-temperature-coefficient sensing device, for detecting the presence and approximately measuring the quantity or concentration of heat-absorptive substances such as water. May be used for sensing a quantity of rainfall or irrigation water, or for detecting and giving an alarm or initiating remediation for leakage of water, oil, or other fluids from confinement to an unauthorized location.

Abstract: A sensor and associated circuitry for sensing and reacting to the presence of a fluid or other material having heat capacity. A positive-temperature-coefficient device initiates a switching step when the amount of heat-capacity material reaches a certain level, or is totally absent. The switching step may trigger an alarm or control circuit to rectify the fluid level.

Abstract: A method for generating an electrical signal and a sensor device (10) for executing the method. The signal is generated because of a change in a fluid-filled space. A sensor element (12) of the sensor device (10) detects the heat transfer over time between the sensor element (12) and the fluid. The sensor element (12), which has a temperature-dependent electrical conductivity and to which a voltage has been applied, is brought to a temperature which lies outside the range of the fluid temperatures. In the passive phase, the fluid is brought to a constant passive temperature by a heat transfer between the sensor element (12) and the surroundings. The sensor device (10) provides a constant passive output voltage. A heat transfer between the sensor element (12) and its surroundings takes place in the active phase by changes in the fluid-filled space. The sensor device (10) provides an active output voltage, which is different from the passive output voltage.