A method of formulating a system of first derivative-explicit differential equations for RLC graphs containing voltage and current sources is given. It is shown that for any connected RLC graph G containing no circuits of voltage sources and no segs (or cut sets) of current sources, there exists a tree T such that all voltage sources and as many C-elements as possible are branches of T and all current sources and as many L-elements as possible are chords of Y. rl he method of formulation is based on properties of the f-circuit, f-seg (or cut set) and element equations of the graph G and tree 7". By combining the algebraic-differential system of equations of G (f-circuit, f-seg and element equations), a detailed expression of the first derivativeexplicit system of differential equations is obtained. The number of equations is equal to the number of C-elements in the tree T plus the number of L-elements in the complement of 7".
Detailed expressions for the initial conditions (t = 0+) for the first derivative explicit system of differential equations for G in terms of the arbitrarily specified t = 0 -values of the variables are also given.