Response compensation of fine-wire temperature sensors

Theoretical analysis of the frequency response of a fine-wire temperature sensor such as a thermocouple or a cold wire was performed, and a strict solution of the response was derived by treating rigorously a boundary condition of heat transport between the temperature-sensing part and its adjoining support. The solution obtained is highly universal and can express the frequency response of both a fine-wire thermocouple and a cold wire with a single equation. The validity of the theoretical solution was examined experimentally, and a response-compensation technique widely applicable to fine-wire temperature sensors was developed based on the theoretical results. In this technique, no special apparatus for calibrating the dynamic response is necessary. The present response-compensation technique can perform fluctuating temperature measurement by a 3.2μm tungsten wire well comparable to that by a 0.63μm platinum wire which is regarded as one of the fastest temperature sensors commercially available.