Constant temperature and constant temperature difference anemometer

摘要

The anemometer determines the cross section flow rate rho W based and comprises a signal generator (G) or transducer, which consists of a hot wire or hot foil and one or more balancing resistances (P,R3) connected to two fixed resistances (R1,R2) in a Wheatstone bridge circuit. A controller circuit balances the bridge. A lineariser network, which may comprise analogue multipliers, calculates the product of transducer current and voltage, UGIG, and squares this to obtain an output voltage, UQ, which is directly proportional to the cross section flow rate, rho W. The linearising network may be a microprocessor and this further compensates the output voltage for temperature variation using a factor (T/T0)^w, using a differential feedback amplifier.