A brushless DC motor configured with an external rotor includes an analysis and control unit, a stator, a rotor, a co-rotating bell, and a sensor that detects an angular position of the rotor. A target with at least one electrically conductive track is attached to the co-rotating bell, and the sensor is configured as an eddy current sensor with at least one coil. The sensor is arranged at a radial distance from the target such that the at least one electrically conductive track at least partly covers the at least one coil. The sensor provides an angle signal as a function of the at least one coil being covered by the at least one electrically conductive track. The angle signal uniquely represents the absolute angular position of the rotor up to 360. A method includes providing an angle signal for the brushless DC motor.

A duty cycle is used in conjunction with a powered oscillator to electronically reduce the current draw by reducing the average tail current and thus reducing the sensor radiated emissions without altering an inductive position sensor. The duty cycle enables an on and an off cycling without altering the hardware but providing the improvements.

A proximity sensor is provided with coils (11, 12) disposed in a pre-set positional relationship, a first distance calculation unit (31) and a second distance calculation unit (32) for calculating first distance information (d1) and second distance information (d2), respectively, from the coils (11, 12) to a detection object (W) on the basis of reception results (voltages V1, V2) of the coils (11, 12), and a position estimating unit (33) for estimating the position, such as distance and azimuth, of the detection object (W) on the basis of the first distance information (d1), the second distance information (d2), and the positional relationship of the coils (11, 12) .

An inductive user interface mechanism for determining displacement by measuring change in inductance caused by an interfering member moving perpendicularly into the core of a coil formed in two parts with a gap between the two parts.

There is provided a signal processing circuit, which improves a signal SN ratio, for a measuring machine. A sensor uses two or more reference signals processed so as to have a mutual predetermined phase difference. The signal processing circuit includes a phase correcting circuit which removes an offset due to a phase shift between the two or more reference signals. The phase correcting circuit includes an offset detecting unit which adds the two or more reference signals and extracts the offset, and a correction processing unit which removes the offset from a sensor signal.

A position sensor, wherein the position sensor detects the movement of a target relative to a sine receiver coil and a cosine receiver coil and generates a corresponding sine signal and a corresponding cosine signal, and a method for error detection of a position sensor.

A three-dimensionally shaped coil can be manufactured at low cost and easily and uses a planar coil array. In the planar coil array, a flexible board comprises: a first planar coil that has a first spiral shape in which a first conductor is wound in a left-handed or right-handed manner with respect to a first center; and a second planar coil in which a second conductor in the same layer as the first conductor formed on the flexible board is wound with respect to a second center in the same manner of winding as the first coil, the second planar coil having an angular misalignment from the first spiral shape, being disposed adjacent to the first planar coil in a predetermined direction, and being electrically connected to the first planar coil. The flexible board is bent, thereby forming a three-dimensionally shaped coil.

In a metal detector, a magnetic field output unit generates an alternating magnetic field, a magnetic field detection unit detects a change in magnetic field caused by an inspection object passing through the alternating magnetic field to output a detection signal, and a control unit detects whether or not metal foreign matter is contained in the inspection object based on the detection signal. A storage unit sequentially stores influence value information including phase information, amplitude information, or a Lissajous waveform obtained based on the detection signal when an accepted product that is determined not to contain metal foreign matter passes through the alternating magnetic field. When the influence value information is changed to exceed a predetermined criterion, the control unit determines that a state of the inspection object is changed, and a notification unit notifies the determination.