Noise characteristics of thermistors: Measurement methods and results of selected devices

Abstract

As part of the development of a spectrally uniform room-temperature absolute radiometer, we have studied the electrical noise of several bulk chip thermistors in order to estimate the noise floor and optical dynamic range. Understanding the fundamental limits of the temperature sensitivity leads inevitably to studying the noise background of the complex electro-thermal system. To this end, we employ a measurement technique based on alternating current synchronous demodulation. Results of our analysis show that the combination of a low-current noise Junction Field Effect Transistor (JFET) preamplifier together with chip thermistors is optimal for our purpose, yielding a root mean square noise temperature of 2.8 μK in the frequency range of 0.01 Hz to 1 Hz.

Study on the Voltage Reference Noise at Sub-Millihertz Frequencies for Developing an Ultra-Stable Temperature Measurement Subsystem

“…At ULFs, the resistors are much more stable than the thermistor [ 27 ], such that , and they have the same resistance value , rendering that: …”

“…where the bridge noise N 2 V T is related to the thermistor noise N 2 R T and resistor noise N 2 R n . At ULFs, the resistors are much more stable than the thermistor [27], such that N R n N R T , and they have the same resistance value R 0 , rendering that:…”