Air-Gas

A sensitive and reliable way to measure airflow is to exploit the predictable relationship between airspeed and the heat dissipated by a sensor exposed to the flow while being held at a constant temperature differential above ambient. The power required to maintain the elevated sensor temperature is proportional to the square root of the airspeed (King`s law). The popular hot-wire anemometer uses this principle, but suffers from the disadvantage of using a relatively fragile airflow sensor, a thin metallic filament...

A previous Design Idea presented a simple flow-to-frequency transducer that easily fits into mP-based measurement systems (Reference 1). You can accumulate and linearize its frequency output by using software without the need for ancillary circuitry. In other applications, however, you might prefer a linearized analog output...