AD596/AD597 J-K Thermocouple Signal Conditioner

This is a AD596/AD597 J-K Thermocouple Signal Conditioner circuit. When operated with J and K type thermocouples, the AD596/AD597 can produce a temperature proportional output of 10 mV/°C. Thermocouples generate low level output voltages which are a function of both the reference or cold junction temperature and temperature being measured. The AD596/AD597 is used to compensate the cold junction temperature. To produce a high level 10 mV/°C voltage output that is a function only of the temperature being measured, the signal of the thermocouple is amplified by The AD596/AD597. Here is the circuit:

The sensitivity of the output voltage to changes in ambient or device temperatures is indicated by the temperature stability of the part: 0.02°C/°C over the +25°C to +100°C is recommended ambient temperature range. Ambient temperature ranges can be  extended by the parts from –55°C to +125°C. However, the temperature stability over this extended range is derived by thermocouple non-linearity at the reference junction. [Circuit’s schematic diagram source: analog.com]