  In this paper we revisit the thermocouple model, as a linear irreversible
thermodynamic energy converter. As is well known, the linear model of the
thermocuple is one of the classics in this branch. In this model we note two
types of phenomenological coefficients: the first comes from some microscopic
models, such as the coefficient associated with the electric conductivity, and
the second comes from experimental facts such as the coefficient associated
with the thermoelectric power. We show that in the last case, these
coefficients can be related to the operation modes of the converter. These
relationships allow us to propose a generalization of the first and second
Thomson's relations. For this purpose we develop the ideas of non-isothermal
linear converters, operated directly (heat engine) and indirect (refrigerator).
In addition to this development we analyze the energy described by these
converters.
