The magnetic flowmeter is a transducer used to measure the flow of electrically conductive fluids. It has the advantage of not presenting any sort of obstruction to the fluid flow during the measurement. This type of flowmeter operates on the principle that a voltage is induced in a conductor when the conductor moves in a magnetic field. Since the voltage depends on the rate at which the conductor moves through the mag- netic field, the strength of the voltage can be used as an indication of the rate of flow of the liquid.
The hot-wire anemometer is a fine resistance wire heated by a current passing through it. If a cooler fluid flows past the wire, heat is removed from it by the fluid. The