Non-bridge NTC thermistor anemometer with programmable sensitivity

Abstract

This paper presents a programmable constant temperature anemometer (CTA) with a voltage control of the negative temperature coefficient (NTC) thermistor's working temperature. The CTA uses a non-bridge regulating circuit, outputting voltage, current and power dissipation signals. Its operation and sensitivity control are tested for NTC temperatures in a 45 to 85°C range, at wind speeds up to 14m/s. The power sensitivity at 25m/s is improved by NTC temperature increase, estimated to be 6.74mW/(m∙s−1) at 85°C. A qualitative analysis of circuit's stability is derived, providing the guidelines for bandwidth optimization. The NTC's resistance is regulated with error of 0.9% for working temperatures over 60°C. The demonstrated programmability of NTC temperature allows for implementation of known temperature compensation and measurement techniques utilizing a single sensor, while permitting continuous sensitivity control. This makes it suitable for measurements with varying ambient conditions.