  We express the link between conductivity and coefficients of Seebeck,
Nernst-Ettingshausen, Peltier, and Thompson and Reghi-Leduc via the temperature
derivative of the chemical potential of a system. These general expressions are
applied to three-, two- and one-dimensional systems of charge carriers having a
parabolic or Dirac spectrum. The method allows for predicting thermoelectric
and thermomagnetic properties of novel materials and structures.
