Zero-offset magnetometer having coil and core sensor controlling period of an oscillator circuit
US5239264A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1991 |
| Grant date | Aug 24, 1993 |
| Priority date | — |
| Expiry date | Nov 14, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetometer technology is provided based on a simple axial sensor which operates using the non-linear nature of saturating magnetic core material. The sensor appears electrically as an inductor with a non-linear inductance that varies both with magnetic field applied externally and the field created by the coil current. By using this sensor as the inductor of an LR relaxation oscillator, a change in applied magnetic field will cause a change in inductance, which will in turn cause a change in the oscillator period. The period of the oscillator can be converted to a digital form by using simple counting techniques. By introducing an enhancement of this scheme whereby two different periods are measured with different oscillator characteristics, the magnetometer will have no output drift when no field is applied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.