There are explanations of dual linear programs in terms of economics like Farmer example on Wikipedia.
In a book Ten lectures on statistical and structural pattern recognition I've found a real-world example of a linear program with a physical interpretation of primal and dual variables.
I'm not good in the theory of electric circuits. If I understand it right, things are the following. There is a circuit with transformer coils, phase rectifiers and power/current sources. The primal variables are voltages and the dual ones are currents. Though, I didn't get the idea: I don't understand how linear programming can help with electric circuits building.
Can you provide a clear explanation of a dual linear program, applied to electric circuits, with appropriate references and images?