A conductivity sensor for measuring the electrical conductivity of a liquid medium having at least a first coil, a current source and a control and evaluation unit, the current source being connected to the first coil. The conductivity sensor has the ability to determine a particularly large range of electric conductivity by at least a first electrode and a second electrode and at least one voltage measuring unit being provided, the voltage measuring unit being connected to the first electrode and the second electrode, the control and evaluation unit being connected to the current source and to the voltage measuring unit, and the first electrode and the second electrode being out of electrical contact with the first coil.

A method for operating an inductive conductivity measuring device that has a transmitting coil with an input and a receiving coil, the transmitting coil and the receiving coil being inductively coupled to one another by an electrically conductive medium. An electrical preset alternating signal is generated and fed to the input of the transmitting coil. The method for operating an inductive conductivity measuring device is improved in that a frequency of a preset alternating signal is varied in a frequency interval, in the frequency interval, a frequency-dependent minimum input impedance at the input of the transmitting coil is determined using a response alternating signal, a minimum frequency of the response alternating signal is determined at the minimum input impedance at the input of the transmitting coil, and a conductivity of the medium is determined using the minimum frequency of the response alternating signal.

In order to avoid an electrode from disturbing a flow of a fluid in a flow channel in case that the electrode of an electric conductivity meter is arranged in the flow channel, the electric conductivity meter comprises two tubular electrodes inside of each of which respectively formed is an inner flow channel where the fluid flows, and an electrode holder that communicates each of the inner flow channels of the two electrodes and that holds the two electrodes. The electrode holder holds the two electrodes by making an engagement with each outer peripheral surface of mutually facing axial direction end parts of the two electrodes.

In order to avoid an electrode from disturbing a flow of a fluid in a flow channel in case that the electrode of an electric conductivity meter is arranged in the flow channel, the electric conductivity meter comprises two tubular electrodes inside of each of which respectively formed is an inner flow channel where the fluid flows, and an electrode holder that communicates each of the inner flow channels of the two electrodes and that holds the two electrodes. The electrode holder holds the two electrodes by making an engagement with each outer peripheral surface of mutually facing axial direction end parts of the two electrodes.

A system for measuring the state of degradation of cooking oil or fat includes at least one fryer pot. A conduit is fluidly connected to the fryer pot for transporting cooking oil from the fryer pot and returning the cooking oil back to the fryer pot. A pump is provided for re-circulating cooking oil to and from the fryer pot. A sensor is disposed in fluid communication with the conduit and measures an electrical property of the cooking oil as the cooking oil flows past the sensor and is returned to the at least one fryer pot.

A shock detector having an electrical detector having a set of water immersible electrodes for detecting hazardous water conditions through the determination of the presence of either an electrical current in a body of water, a voltage in the body of water or a voltage gradient in the body of water and then providing an alert to the existence of hazardous electrical conditions in the body of water which in some cases may transmitted to a power source to shut off a power source thereby removing the hazardous water condition.

A shock detector having an electrical detector having a set of water immersible electrodes for detecting hazardous water conditions through the determination of the presence of either an electrical current in a body of water, a voltage in the body of water or a voltage gradient in the body of water and then providing an alert to the existence of hazardous electrical conditions in the body of water which in some cases may transmitted to a power source to shut off a power source thereby removing the hazardous water condition.

According to an embodiment, a capacitance determination circuit is provided comprising a voltage controlled oscillator configured to generate a frequency signal whose frequency depends on a control voltage supplied to the voltage controlled oscillator, a capacitor coupled to the voltage controlled oscillator wherein the control voltage depends on a voltage across the capacitor and a processing circuit configured to generate, based on the frequency signal generated by the voltage controlled oscillator over a time interval comprising at least one phase in which the capacitor is charged and comprising at least one phase in which the capacitor is discharged, an indication of the capacitance of the capacitor.

Non-contact type measuring apparatus able to detect a difference in signal intensity by transmitting a radio frequency (RF) signal having a predetermined frequency through one of two coil antennas and receiving an induced RF current signal transmitted via a medium through the other coil antennas and detect conductivity and a variation in characteristic of a non-conductor by comparing the signal intensity with a signal intensity comparison table for each frequency, which is stored in a controller by measuring a signal intensity for each frequency in advance, on the basis of the signal intensity for each frequency. The non-contact type measuring apparatus can accurately measure not only various elements using a characteristic in which conductivity is varied according to total dissolved solid, temperature, and an amount of a conductive medium and permittivity change characteristic of a non-conductor, but also conductivity and variation in characteristic of the non-conductor.

A capacitive electrical conductivity sensor is integrated into a water meter. The sensor is used to determine water conductivity, which may be used to determine water quality. A model of a capacitor, a flow of water, and a plastic conduit used to conduct the flow of water passing through a water meter is defined. The model may include a circuit having a constant phase element (CPE) connected to a resistor R.sub.b and a capacitor C.sub.b in parallel. An input signal may be applied to the actual capacitor (not the model) over a range of frequencies. Current flow associated with several frequencies may be used to identify values of Q.sub.0 and alpha of the CPE of the model. A value for the resistor R.sub.b is identified using values obtained from measurements. A conductivity of the flow of water may be derived using input values comprising R.sub.b, and the values of Q.sub.0 and alpha of the CPE of the model.