Title :
Fabrication of reference standard 1 ohm resistors from Evanohm S alloy
Author :
Pritchard, B.J. ; Grime, R.C.
Author_Institution :
CSIRO, Lindfield, NSW, Australia
Abstract :
The fabrication of reference-standard 1- Omega resistors that have characteristics superior to those of the Thomas-type resistor is described. A coil of Evanohm S wire was fabricated into a four-terminal resistor. A program of heat soaking at temperatures below 500 degrees C for varying periods brings the first-order temperature coefficient and the resistance correction at room temperature close to zero. Resistance adjustments are made using an electrolytic etching technique to achieve the required specifications. The heat-treatment program also achieves a low initial drift rate. The finished coil is fitted into a mount incorporating three hinges that support the coil without detracting from its performance.<>
Keywords :
chromium alloys; copper alloys; electric resistance measurement; etching; measurement standards; nickel alloys; resistors; 1 ohm; Evanohm S alloy; Evanohm S wire; Ni-Cr-Cu alloy; Thomas resistor; coil; drift rate; electrolytic etching; first-order temperature coefficient; four-terminal resistor; heat soaking; heat-treatment; mounting; reference standard resistor; resistance correction; Annealing; Coils; Electrical resistance measurement; Etching; Fabrication; Heat treatment; Resistance heating; Resistors; Temperature; Wire;
Conference_Titel :
Precision Electromagnetic Measurements, 1990. CPEM '90 Digest., Conference on
Conference_Location :
Ottawa, Ontario, Canada
DOI :
10.1109/CPEM.1990.110027
