An amplifier and power supply for a stable, high‐frequency, electronic, bristle flowmeter is described. The transducer element is the RCA 5734 tube. The difficulty in applying this tube to blood flow measurements is overcome by use of a 500 000 ohm load resistor instead of the 75 000 ohm value recommended by the manufacturer. The advantages of this device are commercial availability of flow‐sensing element, high signal‐to‐noise ratio, good maintenance of the zero flow base line, response to backflow as well as forward flow, and provision for the recording of either phasic or mean flow.