Abstract: A circuit and method for demodulating at least one modulated signal (e), such as a measuring signal of a sensor. The circuit comprises at least one input (1), with the signal (e) being applied to the input (1), and the input is connected to at least one switched-capacitor network which is configured to demodulate the signal. The circuit permits use even in a small available space.

Abstract: A circuit arrangement (10) for activating a sensor and evaluating its signals, in particular for parametric sensors with complex impedances. The circuit arrangement comprises at least one sensor (2) for acquiring mechanical data. In order to minimize or largely prevent temperature caused disturbances in a constructionally simple layout, the measuring signal, the absolute temperature, and the gradient temperature of the sensor (2) are acquired simultaneously, preferably by means of a microprocessor or microcomputer (3). A corresponding method for activating sensors and evaluating their signals is also described.

Abstract: A device and a method for detecting the position of an object (1), such as an armature (2) of an inlet or outlet valve (3), with the device comprising at least two coils (4, 5), preferably two magnet coils, which can be energized for moving the object (1) between the two coils (4, 5), or used with an evaluation circuit for detecting the position of the object (1). The two coils (4, 5) are alternately used for moving the object (1) between the coils (4, 5) and for detecting the position of the object (1).

Abstract: A method for operating an eddy current sensor (10) with a measuring coil (2) and an evaluation circuit (4) for determining material or geometric parameters of a test object (5), in which the test object (5) is arranged at a distance (d) from the measuring coil (2). The impedance of the measuring coil (2) is evaluated, while the measuring coil (2) is being supplied with an alternating voltage of a predetermined frequency, and the evaluation circuit (4) determines the material and geometric parameters of the test object (5) based on the impedance of the measuring coil (2). The impedance of the measuring coil (2) is determined at an alternating voltage of a first frequency, and the impedance of the measuring coil (2) is determined at an alternating voltage of a second frequency, and the evaluation circuit (4) computes the material and geometric parameters of the test object (5) on the basis of the impedances of the measuring coil (2) at the first and the second frequencies.

Abstract: Eddy current sensor with an exploring coil (2) wound on a coil form (32), with two terminals (6, 7), a source of ac voltage, an electrically conductive measuring probe (3), and an evaluation circuit, wherein the measuring probe (3) is displaceable relative to the exploring coil (2), and the evaluation circuit generates an evaluation signal as a function of the position of the measuring probe (3), wherein the eddy current sensor comprises an electrode (4) with a tap (8) for enabling electrical contact, the electrode forming together with the windings of the exploring coil (2) and an intermediate layer (33) a component with distributed electromagnetic parameters, whose output signals are used to determine the position of the measuring probe (3).

Abstract: A method for operating an eddy current sensor (10) with a measuring coil (2) and an evaluation circuit (4) for determining material or geometric parameters of a test object (5), in which the test object (5) is arranged at a distance (d) from the measuring coil (2). The impedance of the measuring coil (2) is evaluated, while the measuring coil (2) is being supplied with an alternating voltage of a predetermined frequency, and the evaluation circuit (4) determines the material and geometric parameters of the test object (5) based on the impedance of the measuring coil (2). The impedance of the measuring coil (2) is determined at an alternating voltage of a first frequency, and the impedance of the measuring coil (2) is determined at an alternating voltage of a second frequency, and the evaluation circuit (4) computes the material and geometric parameters of the test object (5) on the basis of the impedances of the measuring coil (2) at the first and the second frequencies.

Abstract: An eddy current sensor (1) has at least one measuring coil (2) that can be supplied with an alternating current, and an evaluation circuit (3). The eddy current sensor allows the temperature influences on the impedance of the measuring coil to be reliably compensated with a simple design and an evaluation circuit. For this purpose, the eddy current sensor has a compensating coil (4) which can also be supplied with an alternating current and which is arranged closely to the measuring coil, i.e. in thermal contact therewith, in such a way that the electric fields of compensating coil (4) and measuring coil (2) are orthogonal to each other. More particularly, the measuring coil (2) is in an annular form and the compensating coil (4) is wound around the measuring coil in the form of a torus.

Abstract: A noncontacting displacement sensor (1) is proposed with a measuring coil (2) to which alternating current can be applied, the measuring coil (2) having at least two voltage taps (3), with an electrically and/or magnetically conductive measuring object (5), and with an evaluation circuit (4) for evaluating and, if need be, determining an output voltage that corresponds to the position of the measuring object (5) with respect to the voltage taps (3). To provide the displacement sensor of a structural form that is as compact as possible, the measuring object (5) is arranged and displaceable in the interior of the measuring coil (2), the total impedance of the measuring coil (2) being independent of the position of the measuring object (5).

Abstract: The proposed device comprises a primary detector and a measuring amplifier, the primary converter comprising a central cylindrical core and an external cylindrical core arranged coaxially along a longitudinal axis, a movable member being mounted coaxially with the cores, a measuring winding arranged on the central core along the longitudinal axis in such a manner that the turns of the winding encompass the central core in a transverse direction, and an additional winding having a common electrical connection point with the measuring winding and disposed on one of the cores so that its turns encompass the core in a longitudinal direction and pass through the corresponding central axial opening. The measuring winding and the additional winding are connected with the measuring amplifier, and alternating current voltage is fed to the input thereof.

Abstract: A noncontact distance measuring system with a sensor (2) that draws on alternating current and has a measuring coil (1), an electronic supply/evaluation circuit (3) connected with the sensor (2), and an electrically and/or magnetically conductive test object (4) associated to the sensor (2), the measuring coil being packaged in a preferably cylindrical housing, and the test object (4) at least partially surrounding the coil housing (5) and being movable in its longitudinal direction, is structured so as to reduce the overall length and to avoid the output impedance of the measuring coil from the position of the test object, in that the test object (4) is designed as a ring (6) surrounding the coil housing (5) at a distance, that the measuring coil (1) has at least two voltage taps (7), so that depending on the number of voltage taps (7) either voltage values can be tapped sequentially between the individual voltage taps (7) and a reference potential (8), and that the electronic supply/evaluation circuit (3) i

Abstract: In order to determine the contents of solids in a heated elongated slug of thixotropic metal having a longitudinal axis, there is an apparatus comprising an inductive heating coil with electrical winding. Moreover, a sensor includes at least one measuring coil arranged between the heating coil and the slug. This sensor provides an output signal which corresponds to the contents of solids demanded.