Thermocouple Amplifier with Cold Junction Compensation Explained

A Thermocouple Amplifier with Cold Junction Compensation Circuit is explained in this video that is an example of thermoelectrical temperature sensor signal conditioning circuit design and analysis. This K-Type Thermocouple Amplifier is designed to perform two tasks of signal amplification and zero adjusting to set the intercept to zero for the overall temperature transfer function of the circuit. The circuit is designed with two op amps, a 2.4 volt Zener diode with -0.085% per degree Kelvin temperature coefficient that results in -40.8 micro volt per degree C temperature coefficient which is nearly matching the 40.7 micro volt per degree Seebeck coefficient of Peltier–Seebeck Thermoelectric voltage generation in order to compensate for the unwanted effect of the cold temperature (the non-zero temperature of the copper wire at PCB temperature). The designed Type-K Thermocouple Amplifier maps measured temperature range of 0 to 400 degree Celsius to the 0 to 4 volt range at the output of the circuit achieving a 10 mV per degree Celsius temperature coefficient for the overall amplifier.