NOISE IN HOT-WIRE ANEMOMETERS

An analysis is given of the electronic noise and the signal-to-noise ratio for constant-temperature and constant-current hot-wire anemometers. The analysis shows that both anemometers are equivalent in their signal-to-noise ratio if the noise sources are equivalent and the hot-wires are operated at the same conditions. A discussion of the theoretical results and a comparison of both anemometer types based on these results are given. In addition, some noise measurements on a constant-temperature anemometer and the methods to obtain them are reported and compared with theoretical results. The agreement between measured and theoretical results is rather good. © 1968 The American Institute of Physics.