Browse Prior Art Database

ISOTROPIC MAGNETIC FIELD (H-FIELD) SENSOR

IP.com Disclosure Number: IPCOM000008983D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Jul-29
Document File: 4 page(s) / 125K

Publishing Venue

Motorola

Related People

Ci Zhong Xu: AUTHOR [+3]

Abstract

A magnetic field sensor is provided which employs Hall elements. The measurement is simple to conduct, and the measured value is not dependent on the direction of the field. The sensor can be used for measurement of ambient magnetic tields in the workplace, to enhance worker safety.

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Page 1 of 4

cm MOTOROLA Technical Developments

ISOTROPIC MAGNETIC FIELD (H-FIELD) SENSOR

by Ci Zhong Xu, Karlheinz Kraft and Klaus Dirksmeier

ABSTRACT

  A magnetic field sensor is provided which employs Hall elements. The measurement is simple to conduct, and the measured value is not dependent on the direction of the field. The sensor can be used for measurement of ambient magnetic tields in the workplace, to enhance worker safety.

INTRODUCTION

  This paper relates to the measurement of mag- netic fields. The sensor described has particular application to the routine measurement of magnetic fields in the workplace, in order to ensure compli- ance with international 'health and safety' require- ments.

PROBLEMS TO BE SOLVED

  The level of magnetic field present in workplace environments needs to be measured. This need is being driven increasingly by new health and/or hygienic standards, such as the Russian HS2.1.8/2.2.4.019-94 or ENELECENV 50166-2 etc. These standards are designed particularly to protect

employees in the workplace.

  In particular, many sites around in the world must perform a site-tracking procedure to make sure that there are no radio frequency (RF) fields which exceed limits set in the standards for a frequency

range from 100 kUz to 300 Ghz. These limits relate to the levels to which an employee or customer would be exposed.

  Presently, the monitoring must be performed on a monthly basis for certain work areas, and every year for all work areas. Purchasing presently avail- able commercial equipment would cost about US$ZO,OOO for each site. The reason for the cost of such equipment is the isotropic sensor which it uses.

  Some presently available isotropic magnetic field sensors have to make separate measurements of the components of the magnetic field in three orthogonal directions. These are the Hx, Hy and Hz components of the magnetic field H. From these components the magnetic field H can then be calcu- lated, but this is complicated.

PROPOSED SOLUTION TO THE PROBLEMS

  With the sensor proposed in this paper, very strong magnetic f...