Magnetic field sensor with enhanced sensitivity, internal biasing and magnetic memory
US6727692B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Feb 14, 2002 |
| Grant date | Apr 27, 2004 |
| Priority date | — |
| Expiry date | Feb 18, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A high sensitivity magnetic field sensor is described. The sensing element is a stress-sensitive, negative-magnetostriction, melt-extracted amorphous wire, in which a strong magneto-impendance effect develops when the wire is connected to conventional electronic circuitry, which can be an impedance-meter. An a.c. current is provided to the wire and its relative change in impedance is measured. Simultaneously, the wire is submitted to a longitudinal d.c. magnetic field, H. A saturating d.c. field pulse is also applied to this wire at the beginning of the operating cycle. Tensile stress is further generated in the wire by pulling one end of the wire with a given force. This stress can be fine-tuned for sensitivity and bias with the help of a suitable mechanism. All these elements are packaged in a rugged non-magnetic enclosure, which permits easy and reliable connection of the sensor to said conventional electronic circuitry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.