Measuring Measuring Air Velocity – Basics

The sensor consists of two resistive mesh deposited on a thin glass substrate using cutting-edge thin-film technology. One of the two resistors operates as a temperature sensor and measures the temperature of the flowing medium.

Using electrical current, the other resistive mesh is heated and kept at a constant temperature offset ∆Th-a relative to the temperature of the medium.

The medium (air or gas) flowing over the sensor with velocity v is cooling the heated resistor. The power P necessary to keep the temperature offset between heater and tem- perature resistor constant is a measure for the air velocity.