Sensitivity analysis and automatic adjustment of a controlled-temperature thermoresistive-based anemometer

This paper presents an architecture of a hot-wire anemometer that adjusts the difference between the sensor temperature and the fluid temperature and maximizes the sensitivity of the output quantity (voltage or pulse width) in relation to the input quantity (velocity). Analyses were made for the PTC and NTC sensors type and for output in pulse width or analog voltage type. It was verified that, for PTC sensors the sensitivity is as higher as the difference between the temperature of the sensor and the fluid temperature. For a NTC, on the other hand, the sensitivity is maximum when the difference of temperature is 30 K (for one commercial sensor parameters).