CALIBRATING METHOD OF CURRENT DETECTION TYPE THERMOCOUPLE OR THE LIKE, CALIBRATION METHOD OF OFFSET OF OPERATIONAL AMPLIFIER, CURRENT DETECTION TYPE THERMOCOUPLE, INFRARED SENSOR AND INFRARED DETECTOR

摘要

To calibrate a thermocouple, a calibrating thermocouple formed of the same thermocouple material as that of a detecting thermocouple is used to determine in advance the absolute thermoelectric power E<SUB>ro</SUB> of the calibrating thermocouple. The detecting thermocouple is assumed to have the same E<SUB>ro</SUB>. The internal resistance r<SUB>s</SUB> of the detecting thermocouple is determined, and a shortcircuit current value I<SUB>s</SUB> by a measured temperature difference ?Ts is measured by an operational amplifier to determine a measured temperature difference ?Ts. Offset calibration is also performed on the operational amplifier. A thermocouple and a switch are connected to the inverting input terminal of the operational amplifier to enable also sensor selection. These are connected to a non-inverting input terminal, and an equivalent current detection type thermocouple having a small resistance r connected to the inverting input terminal is used to enable switching between a plurality of thermocouples. Accordingly, easy and accurate temperature calibration and correction are permitted even if a hot-junction or a cold-junction is formed on a cantilever or a diaphragm.