The procedure for determining the state of the system is called state variable analysis. State-variable analysis, or state space analysis, is a procedure that can be applied both to linear and non linear circuits. It is also applicable for circuits time variant and time invariant parameters.
A state-variable based approach minimizes computation time and memory requirements. It allows the use of parameterized nonlinear device models, thus improving robustness.
To design state equation for an electric network the state variables specify the energy stored in a set of