The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jan. 08, 2002

Filed:

May. 03, 2000
Applicant:
Inventors:

Seung Min Lee, Kyonggi-do, KR;

Seung Hyun Moon, Kyonggi-do, KR;

Byung Du Oh, Seoul, KR;

Assignee:

LG Electronics Inc., Seoul, KR;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 3/3022 ; G01R 3/3035 ;
U.S. Cl.
CPC ...
G01R 3/3022 ; G01R 3/3035 ;
Abstract

An apparatus and method for measuring a second-order gradient of a magnetic field using a super conductor quantum interference device (SQUID) which obtains the second-order gradient of the magnetic field with a simple-constructed and low-priced measuring apparatus having three SQUID sensors and one differential circuit only. The apparatus includes first to third SQUID sensor driving circuits for detecting respective surrounding magnetic fields and outputting corresponding currents, respectively, a first coil for producing a magnetic field according to the current outputted from the first SQUID sensor driving circuit and feeding the produced magnetic field back to the first SQUID sensor driving circuit, a second coil for producing a magnetic field according to a sum of the currents outputted from the first and second SQUID sensor driving circuits and feeding the produced magnetic field back to the second SQUID sensor driving circuit, a third coil for producing a magnetic field according to a sum of the currents outputted from the second and third SQUID sensor driving circuits and feeding the produced magnetic field back to the third SQUID sensor driving circuit, and a differential amplifying section for differential-amplifying voltages outputted from the second and third SQUID sensor driving circuits.


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