According to one embodiment, a sensor includes a base including a first face including a first face region, and a first structure body fixed to the first face region. The first structure body includes a first support portion fixed to the first face region, a second support portion fixed to the first face region, a first movable portion, and a first fixed electrode fixed to the first face region. The first movable portion is supported by the first and second support portions and apart from the base in a first direction crossing the first face region. The first movable portion includes a first movable electrode facing the first fixed electrode, and a first conductive member. A first current flows the first conductive member along a second direction crossing the first direction. A first gap is provided between the first fixed electrode and the first movable portion.

An electromagnetic field sensor includes a conductor plate, a signal output terminal to output a potential difference between the conductor plate and the signal output terminal, and a linear conductor including a first end electrically connected to a plate face of the conductor plate and a second end opposite to the first end and provided with a signal output terminal. The electromagnetic field sensor includes a loop plane that is formed by the conductor plate and the linear conductor and orthogonal to a plate face of the conductor plate when viewed from the side.

Flow meter and method for measuring the flow velocity of an oil continuous multiphase flow, said flow including water droplets. The flow meter including at least one magnetic field generator configured to provide a magnetic field with a known strength into said flow, the flow meter also including at least one sensor for measuring the charge at the sensor relative to a ground level, the sensor being positioned at a distance from the center of the magnetic field axis and the flow axis, in essentially the same axial position as the magnetic field axis, wherein the meter also including a calculating means for calculating a measure of the flow velocity based on the measured charge.

A sensor device for detecting voltage in a conductor cable includes a sense electrode to be disposed over a surface of the conductor cable to cover a sense region having a sense axial width and a sense circumferential length and a reference electrode to be disposed over the surface of the conductor cable to cover a reference region. The reference region has an axial position adjacent the axial position of the sense region and has a reference circumferential length greater than the sense circumferential length. The sensor device further includes a charge measurement circuit connected in series between the sense electrode and the reference electrode to measure a charge measurement and circuitry to compare the charge measurement to a threshold to detect a presence of the voltage in the conductor cable.

According to one embodiment, a sensor includes a base including a first face including a first face region, and a first structure body fixed to the first face region. The first structure body includes a first support portion fixed to the first face region, a second support portion fixed to the first face region, a first movable portion, and a first fixed electrode fixed to the first face region. The first movable portion is supported by the first and second support portions and apart from the base in a first direction crossing the first face region. The first movable portion includes a first movable electrode facing the first fixed electrode, and a first conductive member. A first current flows the first conductive member along a second direction crossing the first direction. A first gap is provided between the first fixed electrode and the first movable portion.

A current detection circuit includes a coil that is constituted by a metal wiring formed on a semiconductor substrate, a resistor that is provided in a position near the coil on the semiconductor substrate, constituted by a metal wiring formed on the semiconductor substrate, which is made of a metal material being same as that of the coil, and arranged so as to prevent any magnetic field from being generated due to a current flowing in the resistor, an output circuit that outputs currents in accordance with a resistance ratio between the coil and the resistor to the coil and the resistor correspondingly through a common terminal, and a detection circuit that detects the current flowing in the resistor to thereby detect the current flowing in the coil.

According to one embodiment, a magnetic sensor includes a first magnetic element, a conductive member including a first corresponding portion, an element current circuit configured to supply an element current to the first magnetic element, and a first current circuit configured to supply a first current to the first corresponding portion. The first corresponding portion is along the first magnetic element. The first current includes an alternating current component. The first current includes a first duration of a first current value of a first polarity, a first pulse duration of a first pulse current value of the first polarity, a second duration of a second current value of a second polarity, and a second pulse duration of a second pulse current value of the second polarity. The second polarity is different from the first polarity.

Each of three magnetic sensors is positioned on a first virtual line that passes the centers of two magnetic shields in the width direction and is perpendicular to a virtual plane, so a value detected by the magnetic sensor is less likely to be influenced by an external magnetic field. The first virtual line and the center of a conductor intersecting the first virtual line are separated from each other by a certain distance. Therefore, even if a distance from the center of the conductor in the width direction to the magnetic sensor is short, it is possible to improve, on a high-frequency side, frequency characteristics in the detection sensitivity of the magnetic sensor for the frequency of the current under measurement.

There is provided a ring-shaped magnetic core that forms a closed magnetic circuit that encloses a measured electrical path, a magneto-electric converter that detects magnetic flux inside the magnetic core and outputs an electrical signal with an amplitude in keeping with a quantity of the magnetic flux, a coil that is formed on the magnetic core and is supplied with a negative feedback current generated based on the electrical signal, and an internal shield member disposed at least in a vicinity of the magneto-electric converter and the coil. A first gap that increases a magnetoresistance of a closed magnetic circuit, which is a closed magnetic circuit for leakage flux that leaks from the magnetic core and includes the internal shield member, a part of the magnetic core where the coil is formed, and the magneto-electric converter, is formed in the internal shield member.

An illumination device is provided. The illumination device includes a light source and a current path configured to transport a supply current to the light source. Further, the illumination device includes a sensor configured to contactlessly measure a current strength of the supply current in the current path and to output a measurement signal indicative of the measured current strength. The illumination device additionally includes processing circuitry coupled to the sensor and configured to determine the optical output power of the light source based on the measured current strength indicated by the measurement signal.