| 摘要 |
PROBLEM TO BE SOLVED: To detect the abnormal state of a flow rate signal through a resistance element without supplying direct current to a detection electrode.SOLUTION: A signal amplifier circuit 12 has: one input terminal thereof connected to a flow rate signal input terminal T1; the other input terminal connected to a flow rate signal input terminal T2; and an FET input type differential amplifier outputting from an output terminal an amplification output signal V1 obtained by subjecting a flow rate signal to differential amplification. An abnormality detection circuit 13 detects abnormality of the flow rate signal by comparing the potential of the amplification output signal V1 to an upper limit reference potential Vj and a lower limit reference potential -Vj. |
