Electromagnetic Flowmeter Technical Description The Magnetic-Inductive Flowmeter exploits Faraday's induction law. This law states that a conductor in motion in a magnetic field produces a voltage. In this experimental set-up the conductor in motion is the water, the magnetic field in the area through which the flow passes is generated by a switched, d.c. changing polarity. The voltage induced in the magnetic field is proportional to the flow rate and is acquired using 2 insulated electrodes. This measuring device is used predominantly in industry and is very precise.