Joulean heat

This agrees with the expression for Joulean heat (Section 3.1), which played a prominent role in the quantitative establishment of the first law of thermodynamics. 

The basic element in a thermopile is a junction between two dissimilar conductors having a large Seebeck coefficient 0. To perform efficiently a large electrical conductivity a is required to minimize Joulean heat loss and a small thermal conductivity K to minimize heat conduction loss between the hot and cold junctions of the thermopile. These requirements are incompatible and we find that in common with other thermoelectric devices (Goldsmid [3.12]) the best choice of thermoelectric material is that for which a0 K is a maximum and that this occurs for certain heavily doped semiconductors, for example BijTcj and related compounds. To make an efficient thermal infrared detector the device must also be an efficient absorber o f the incident radiation and must have a small thermal mass to give as short a response time as possible. 

---