Carbon Resistors as Low Temperature Thermometers

Abstract

Several specific types of carbon resistors (8 Allen-Bradley and 2 Speer) have been evaluated and compared as low temperature thermometers. Some of the samples demonstrated a reproducibility of about 0.5 mK on cycling between room and helium temperatures after they had been aged. Low resistance types (nominally 2.7 and 10 Ω) exhibited an abrupt change in their resistance-temperature relationship at 20 K. Standard type BB and EB Allen-Bradley resistors are useful thermometers; in addition to their reproducibility, they have a smooth resistance-temperature characteristic which does not have a minimum and which has a useful temperature coefficient throughout the range 4–300 K.