Sensor assembly for measuring current as a function of magnetic field gradient

US5621377A · kind A · utility

Assignee

• Lust Electronic-Systeme GmbH · DE

Inventors

• Fritz Dettmann · Solms, DE
• Uwe Loreit · Wetzlar, DE

Key dates

• Filing date: Oct 10, 1995
• Grant date: Apr 15, 1997
• Expiry date: Oct 10, 2015

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/096
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To measure magnetic field gradients is difficult because sensor elements available for this have only a limited linearity range due to their sensitivity which is strongly dependent on the temperature and on auxiliary-field magnetic fields and furthermore this sensitivity has a significant sample dispersion. Whereas now the arrangement of a a Wheatstone bridge with magnetoresistive resistors is such that on the one hand two symmetrical areas are provided, in each area of which a resistor of a bridge branch is arranged, and that moveover all other building elements are also designed with a high degree of symmetry. With this a symmetrical temperature gradient is created in the sensor chip, which gradient does not influence the output signal of the bridge. A temperature-dependent zero-point drift does also not exist. The changeable resistor needed for trimming is as the single singular structural part directly arranged on the central axis and also does not interfere with the measurement. The arrangement is particularly suited for the potential-free measurement of the current intensities.