Abstract: An oscillating-ball flowmeter for accurately measuring and transmitting extremely low flow rates. The meter includes a vertically-positioned flow tube having a ferromagnetic ball therein which is subjected to the force of gravity as well as the drag force imposed thereon by the upward flow of fluid being metered. An electro-optical sensor associated with the tube produces a control signal when the ball is intercepted by a light beam. This signal activates a magnet driver which energizes an electromagnet positioned above the sensing beam to generate a magnetic force that lifts the ball upwardly away from the light beam. The driver is thereafter de-activated to cause the lifted ball to fall and again intercept the light beam to re-activate the driver to repeat the cycle.