Thermocouple wires are intended to be electrically floating in order to detect temperature by producing the Seebeck voltage created by two dissimilar metals. This small voltage is amplified to an easily measurable level by an amplifier. To protect the input terminals of the amplifier in the event that the thermocouple is shorted to a high voltage potential, series resistance and clamp diodes can be added.
The LTC6078 dual, low offset, low noise operational amplifiers with low power consumption and rail-to-rail input/output swing. Input offset voltage is trimmed to less than 25μV and the CMOS inputs draw less than 50pA of bias current. The low offset drift, excellent CMRR, and high voltage gain make it a good choice for precision signal conditioning. Each amplifier draws only 54μA current on a 3V supply. The micropower, rail-to-rail operation of the LTC6078 is well suited for portable instruments and single supply applications. LT1025 compensates for cold junction over 0°C TO 100°C.