The transistor as an anemometer

Silicon flow sensors

“…Originally, metal resistors were used. In this case, and in some later semiconductor anemometers, both heating and temperature measurement functions were performed by a single component: a temperature-dependent resistor (or thermistor) [4] or a transistor [5].…”

“…Also a self-heating transistor can be used as a thermal anemometer [5]. The use of a transistor (or diode) to measure temperature relies on the dependence of the pnj unction characteristics on temperature.…”

“…For silicon this results in a temperature sensitivity of about -2mV/K at constant collector current [6]. The basic structure of [5] is shown in Fig. 3.…”