Abstract: A circuit arrangement for a bi-directional output electromagnetic flowmeter including a polarity-detecting circuit arranged to detect the polarity of an input derived from the flowmeter. Means are provided to invert the input polarity and switching means are provided to select the inverted or non-inverted signal in accordance with the output of the polarity-detecting circuit. Thus a constant polarity output signal is obtainable at all times, even though the flow direction in a flow tube changes from time to time.