| 摘要 |
A chemical substance detection apparatus comprising a plurality of chemically sensitive elements constructed as an insulation gate field effect transistor formed on one or different substrates and including chemically sensitive portions selectively sensitive to different specified substances and one reference electrode, at least the chemically sensitive portions as well as the one reference electrode being brought into contact with the same test substance so as to detect various specified substances in the test substance, characterized by comprising reference resistors, first amplifiers operative to adjust gain thereof, a differential amplifier in common to all of said amplifiers and applying its output voltage to the reference electrode and a reference gate bias voltage source connected to the input terminals of the differential amplifier and supplying the reference gate bias voltage thereto. |
