A computer-controlled current-comparator-based four-terminal resistance bridge for power frequencies

Author

So, Eddy ; Djokic, B.

Author_Institution

Inst. for Nat. Meas. Stand., Nat. Res. Council of Canada, Ottawa, Ont., Canada

Volume

50

Issue

2

fYear

2001

fDate

4/1/2001 12:00:00 AM

Firstpage

272

Lastpage

274

Abstract

A current comparator technique is applied to four-terminal resistance measurements for obtaining a highly accurate AC resistance bridge at power frequencies of 50 to 60 Hz. Active circuits are used to establish equal voltage drops between the potential terminals of the two resistances being compared. The bridge is suitable for measuring resistances from 10 μΩ to 100 kΩ. A cascading technique using two two-stage current transformers provides extension of the ratio range to 100000000 with a maximum applied current of 10000 A. The bridge features measurement with a resolution of one part in 10⁷. The total combined uncertainty (2 σ) of the bridge, including the range extenders at power frequencies, is estimated to be less than 5 μΩ/Ω

Keywords

active networks; bridge circuits; cascade networks; computerised control; computerised instrumentation; current comparators; current transformers; electric current control; electric resistance measurement; peripheral interfaces; 10 muohm to 100 kohm; 50 to 60 Hz; IEEE 488 interface; active circuits; cascading technique; computer-controlled current-comparator-based; equal voltage drops; four-terminal impedance; four-terminal resistance bridge; highly accurate AC resistance bridge; potential terminals; power frequencies; total combined uncertainty; two-stage current transformers; Active circuits; Bridge circuits; Capacitors; Current measurement; Current transformers; Electrical resistance measurement; Frequency estimation; Impedance; Resistors; Voltage;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.918119

Filename

918119