A reluctance transducer includes a soft ferromagnetic yoke and a soft ferromagnetic core element, which is movable relative to the yoke. Two permanent magnets bear the core element. The permanent magnets are arranged relative to each other and to the yoke so that the reluctance transducer has a good linear relationship between displacement and force. The reluctance transducer can be applied as stiffness compensating element. The reluctance transducer can include an electrical winding to allow its application as a magnetic bearing, an actuator or as a displacement, velocity or acceleration sensor with improved intrinsic linearity.

A reluctance transducer includes a soft ferromagnetic yoke and a soft ferromagnetic core element, which is movable relative to the yoke. Two permanent magnets bear the core element. The permanent magnets are arranged relative to each other and to the yoke so that the reluctance transducer has a good linear relationship between displacement and force. The reluctance transducer can be applied as stiffness compensating element. The reluctance transducer can include an electrical winding to allow its application as a magnetic bearing, an actuator or as a displacement, velocity or acceleration sensor with improved intrinsic linearity.

An athermal open-loop hung mass accelerometer configures the CTE of the sensor heads such that any growth by the body in response to a body temperature gradient along the longitudinal axis is offset by the growth of the sensor heads in the equal and opposite direction to null the effects of the temperature gradient. In many configurations, the sensor head CTE is strictly less than the body CTE and typically between 60-80% of the body CTE to null the effects of the predicted body temperature gradient.

An athermal open-loop hung mass accelerometer configures the CTE of the sensor heads such that any growth by the body in response to a body temperature gradient along the longitudinal axis is offset by the growth of the sensor heads in the equal and opposite direction to null the effects of the temperature gradient. In many configurations, the sensor head CTE is strictly less than the body CTE and typically between 60-80% of the body CTE to null the effects of the predicted body temperature gradient.

An apparatus and use of the apparatus for monitoring a current-carrying device wherein at least one acceleration sensor produces acceleration measurement values and a communication device transmits produced acceleration measurement values. A power supply unit is for the acceleration sensor and the communication device. The power supply unit includes an induction plate of a metallic material and a conductor loop extending around the induction plate and produces a power supply for the acceleration sensor and the communication device exclusively through induction from an electromagnetic alternating field of the current-carrying device. The apparatus can be positioned in a closed housing having a housing wall and the induction plate can be at least a subregion of the housing wall.

An apparatus and use of the apparatus for monitoring a current-carrying device wherein at least one acceleration sensor produces acceleration measurement values and a communication device transmits produced acceleration measurement values. A power supply unit is for the acceleration sensor and the communication device. The power supply unit includes an induction plate of a metallic material and a conductor loop extending around the induction plate and produces a power supply for the acceleration sensor and the communication device exclusively through induction from an electromagnetic alternating field of the current-carrying device. The apparatus can be positioned in a closed housing having a housing wall and the induction plate can be at least a subregion of the housing wall.

An electronic device is based on a single crystal semiconductor substrate. A cavity is formed in the semiconductor substrate. Further, a movably suspended mass is defined by one or more trenches extending from one side of the semiconductor substrate to the cavity. A first electrode layer is provided on the suspended mass. Further, a cover layer covering the suspended mass is provided. The cover layer includes a second electrode layer arranged opposite to the first electrode layer and spaced therefrom by a gap.

An electronic device is based on a single crystal semiconductor substrate. A cavity is formed in the semiconductor substrate. Further, a movably suspended mass is defined by one or more trenches extending from one side of the semiconductor substrate to the cavity. A first electrode layer is provided on the suspended mass. Further, a cover layer covering the suspended mass is provided. The cover layer includes a second electrode layer arranged opposite to the first electrode layer and spaced therefrom by a gap.

An accelerometer closed loop control system comprising: a capacitive accelerometer comprising a proof mass moveable relative to first and second fixed capacitor electrodes; a PWM generator to generate in-phase and anti-phase PWM drive signals with an adjustable mark/space ratio, wherein said drive signals are applied to the first and second electrodes such that they are charged alternately; an output signal detector to detect a pick-off signal from the accelerometer representing a displacement of the proof mass from a null position to provide an error signal, wherein the null position is the position of the proof mass relative to the fixed electrodes when no acceleration is applied; a PWM servo operating in closed loop to vary the mark/space ratio of said PWM drive signals in response to the error signal so that mechanical inertial forces are balanced by electrostatic forces.

An accelerometer closed loop control system comprising: a capacitive accelerometer comprising a proof mass moveable relative to first and second fixed capacitor electrodes; a PWM generator to generate in-phase and anti-phase PWM drive signals with an adjustable mark/space ratio, wherein said drive signals are applied to the first and second electrodes such that they are charged alternately; an output signal detector to detect a pick-off signal from the accelerometer representing a displacement of the proof mass from a null position to provide an error signal, wherein the null position is the position of the proof mass relative to the fixed electrodes when no acceleration is applied; a PWM servo operating in closed loop to vary the mark/space ratio of said PWM drive signals in response to the error signal so that mechanical inertial forces are balanced by electrostatic forces.