| 摘要 |
An electromagnetic flowmeter includes: a detector for detecting a flow rate voltage; a shielded cable having an inner conductor provided around a cable core to which the flow rate voltage is applied from the detector; and a converter for receiving the flow rate voltage via the shielded cable, and performing a signal processing on the received flow rate voltage so as to output the processed flowrate voltage, wherein a preamplifier of the converter includes: an input circuit which is connected between the cable core and a common voltage point and has an input voltage dividing point for dividing the flow rate voltage; a main amplifier circuit which amplifies the flow rate voltage; and a feedback voltage distribution section which receives an output voltage from the main amplifier circuit, and distributes the output voltage as positive feedback voltages to the inner conductor and the input circuit respectively with different ratios.
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