2. Appropriate technologies

The need to reduce the size of thermoelectric couples, which we use to call thermocouples and then microthermocouples, is linked to the need to improve the intrinsic characteristics of sensors, both dynamically and spatially. The smaller the conductors, the more spatially limited the sensitive zone of the thermocouple, which is the material interface between the two conductors that make it up.

It's easy to show that the response time of a small thermoelectric junction in a convective environment decreases linearly with wire diameter, in the case of soldered wires, and more generally with the mass of the sensor. This relationship remains valid in other heat exchange situations (conduction or radiation). However, many authors have established a clear link between the nature of this exchange and the value of this response time, so that it has gradually become accepted...