Studies on a Hot Wire Anemometer

The present paper deals with some improvements successfully introduced to an anemoneter by the authors. The sensitiveness of a hot wire anemometer is generally known to decrease as the air velocity increases. This，however，was improved to some extent by adopting the following method. Two pieces of Pt-wire for the hot wire，on e in ap arallel direction with the air current and the other perpendicular to the former were stretched. Fluctuation of the pointer of the meter indicating the air velocity was minimized by applying an over-damped meter. Efforts were also made to minimize the error due to the voltage drop of electric source. The hot wire anemometer thus obtained proved to be useful in some mines and factories