Please select the most similar patent number from A, B, C and D. Which number is?
A closed-loop axisymmetric magnetic circuit magnetic core coil component for a Hall current sensor includes two skeletons, a magnetic core and coil windings. The skeletons include an inner skeleton and an outer skeleton, wherein the inner skeleton is wound with a secondary coil winding, and the outer skeleton is wound with a primary coil winding. The inner skeleton and the outer skeleton are inserted towards and locked by each other, and a magnetic core slot and jack are provided on the skeletons. A magnetic core is formed by inserting multiple layers of riveting magnetic sheets with different widths towards each other. The magnetic core is of an axisymmetric magnetic circuit structure, and a single air gap is located at the end of the axis of symmetry near the magnetic core, with Hall elements being provided within the air gap. The magnetic core is mounted in the magnetic core slot and jack of the skeletons, and coil windings on the inner and outer skeletons are located on the axis of symmetry of the magnetic core, and the magnetic core coil component is mounted on a printed circuit board. The magnetic core coil component is of a simple structure, is convenient to mount and is of high precision.
A: A high-precision cross-core open-loop electronic circuit for a Hall current sensor includes an instrumentation amplifier and 2n Hall elements (H1-H2n), wherein the 2n Hall elements are driven respectively using positive and negative mirror constant current source groups of n linear temperature compensation circuits with sensitivity temperature drift to extract a voltage from the input ends of the Hall elements to perform proportion adjustment and temperature tracking compensation on the zero-point voltage of a current sensor; the differential output ends of the Hall elements are respectively connected to a same-phase end and a reverse-phase end of the instrumentation amplifier through the same resistor, realizing the differential output of the 2n Hall elements to calculate the arithmetic mean value; the Hall elements are graded according to the magnitude of positive and negative values of the offset voltages thereof, and the Hall elements, of which the offset voltages are in the same grade while the polarities are reversed, are matched one by one, and are mounted along an identical orientation of an annular magnetic core; and the resistance of an RC filter is within the range for outputting a negative feedback of the amplifier. Provided is an electronic circuit for a high-precision cross-core open-loop Hall current sensor of a simple structure and low costs while the measurement is more precise, belonging to the field of electronic circuitry for a Hall current sensor.
B: An AC permanent-magnet drain pump comprises a pump body (10), a pump cap (1), an impeller (2), a stator assembly, and a rotor assembly. The stator assembly comprises a stator coil (7) and a stator core (8), the rotor assembly comprises a rotation shaft (11), a magnetic core (15) penetrating the rotation shaft, a shaft sleeve (93a) secured on the rotation shaft, and at least one limiting rib provided on the outer wall of the shaft sleeve. The stator assembly and the rotor assembly are mounted in the pump body (10). A rotor base (17) for supporting the rotor assembly is provided in the pump body (10), and an inwardly concaved arc portion of the stator core (8) is embedded in the rotor base (17). The rotor assembly further comprises a start mechanism, for driving the rotation shaft to rotate as the magnetic core rotates. The start mechanism has a start sleeve (93b) that is secured at one end of the magnetic core, and the start sleeve (93b) is made of a non-magnetic material. The AC permanent-magnet drain pump has the advantages of a small magnetic path air gap between the stator core and the magnetic core, high product use efficiency, small structural size, low working noise, desirable heat dissipation, large start torque of the start mechanism, and stable starting.
C: An AC permanent-magnet drain pump comprises a pump cap (1), a pump body (10), a magnetic core (15), a rotation shaft (11), a stator core (8), and a coil (7). The coil (7) winds on a coil former, the stator core (8) is assembled to the coil (7), and the pump body (10) is a case body integrally formed through injection molding and surrounding the contour of the coil (7), the coil former, and the stator core (8) that are assembled together. The case body defines an opening on the top and extends, through the opening, to a magnetic core accommodation space (10.1) for accommodating the magnetic core (15). A top opening of the magnetic core accommodation space is provided with a support structure for supporting the bearing of the rotation shaft. The pump body (10) comprises a first pump body portion (10a) and a second pump body portion (10b), and the inside of the second pump body portion (10b) is provided with a cylindrical rotor base (17) for supporting a rotor assembly. The magnetic core accommodation space (10.1) is encircled by the inner surface of the rotor base (17). An inwardly concaved arc portion of the stator core (8) is embedded in the rotor base (17). The AC permanent-magnet drain pump reduces a magnetic path air gap between the stator core (8) and the rotor, thereby improving the use efficiency of the product, reducing the structural size of the pump body, reducing the manufacturing cost of the product, preventing the pump body from resonating and making a noise, and enhancing the heat-dissipation performance of the pump.
D: A borehole transient electromagnetic radial long-range detection and observation system. The system comprises two three-component transceiving probes and a control probe, which is arranged between the two three-component transceiving probes, wherein each of the three-component transceiving probes comprises an outer framework; a transmitting coil is wound outside the outer framework; a first inner framework, a central inner framework and a second inner framework are successively arranged in the outer framework in an axial direction; a ferrite core is placed in the central inner framework, horizontal-component receiving coils in X and Y directions are respectively wound outside the central inner framework in a long edge direction; ferrite cores are placed in both the first inner framework and the second inner framework, and receiving coils in a Z direction are respectively wound outside the first inner framework and the second inner framework; and the probe parameters of the two three-component transceiving probes are different. Further disclosed are a borehole transient electromagnetic radial long-range detection and observation method and a method for processing data of borehole transient electromagnetic radial long-range detection and observation.
Answer: A