TEMPERATURE MEASURING CIRCUIT

• Main Author: YOSHIHARA TAKAO
• Format: Patent
• Language: English
• Published: 28.08.1985
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; MEASURING QUANTITY OF HEAT; MEASURING TEMPERATURE; PHYSICS; TARIFF METERING APPARATUS; TESTING; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR

PURPOSE:To widen a measurement range by connecting successively program gain amplifiers which are switched for the resistance ratio of a bridge circuit, a linearizer, and a circuit which makes a bias correction of every lower-limit temperature of every element. CONSTITUTION:The scanning circuit from a microcomputer 12 is outputted to the 1st and the 2nd multiplexers 4 and 13 and thermistors 1-3 and resistors 81- 83 of a bridge circuit 200 for resistance variation detection are switched to equalize characteristic curves of the thermistors 1-3 and also linearize them through one linearizer. Further, the program gain amplifier 14 is connected in front of the linearizer 10 so as to eliminate difference in span width when the thermistors 1-3 and resistors 81-83 are combined. Further, a bias correcting circuit 15 is interposed in order to correct and input the bias value at every minimum in- use lower-limit temperature of the thermistors 1-3 to an A/D converter 11. Consequently, the thermistors having different temperature ranges are used in combination.