K. M. Browne
Thermodynamic Steady States in Simple Electrical Circuits
Electrical circuits provide good examples of systems which gravitate towards the three
possible thermodynamic conditions of equilibrium, metastability or dissipative steady
state. Circuits are driven towards any one of the three conditions simply by increasing
total entropy or decreasing available energy. The thermodynamic condition for steady
state conduction in a number of simple LCR and hot filament circuits is found to be
1/(dstot/d?) = 0 or 1/(deavail/d?) = 0 where stot and eavail are the total entropy and
available energy of the system and its surroundings, and ? is any single valued
variable which describes the condition or state of the total system. This is the inverse
of the equilibrium and metastable conditions. It holds for all systems examined,
whereas the Onsager-Prigogine principle, dstot/dt = 0 at steady state, holds only in
one case. This shows that the principle is not the causative principle of the steady state.
As expected, the analysis also demonstrates that electric circuit theory is fully
consistent with the second law of thermodynamics as well as with the first.
Journal of Non-Equilibrium Thermodynamics, Walter de Gruyter
Print ISSN: 0340-0204
Volume: 28, 05/2003
Pages: 147 - 165
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