Sensor apparatus capable of preventing high frequency noise

摘要

A sensor apparatus is capable of removing RF noise. The sensor apparatus is comprised of a first power supply line connected to a power supply terminal; a second power supply line separately branched from the first power supply line and connected thereto; an output line; and a sensor circuit unit connected to the first power supply line so as to receive power therefrom, and for detecting a condition of an article under measurement to output a detection signal to the output line. In this sensor apparatus, the sensor circuit unit includes an operational amplifier operated by accepting the power supplied from the second power supply line, which performs the detection operation; a first filter circuit is connected to the first power supply line defined from a branch point between the first power supply line and the second power supply line to the first power supply line; a second filter circuit is connected to the second power supply line; and a third filter circuit is connected to the output line.