Abstract: A pair of concentric electrodes are mounted at one end of a housing fixedly supported on a body and positioned in a fluid, the flow of which is to be measured relative to the body. A permanent magnet is rotatably mounted in the housing proximate to the electrodes and is rotatably driven. Reference signal generating means is also mounted in the housing to generate a pair of pulsating reference signals having a predetermined phase relationship with each other and with the rotation of the magnet. Alternating current signals are generated between the electrodes, these signals having a magnitude and phase in accordance with the speed and direction of fluid flow relative to the electrodes.