The differential voltage is amplified using the instrumentation
amplifier.This is the inference we know from instrumentation
amplifier...
View page
A instrumentation amplifier is a special purpose linear
amplifier used to amplify low level signals. These are used in many
industrial and medical applications.
View page
You use a thermocouple as the input to the amplifier
circuit.
View page
Here is qn excellent article that explains step by step: