Summary of lectures . Chuvash. Unt, Cheboksary, 2001. 96 s. Theory of Transition Processes in Linear Electrical Circuits . Basic Concepts and Definitions . Classical method of calculation of transients in linear electrical circuits. Transition process in second-order chains. Operator method of calculation of transition processes. Transition from image to original. Decomposition Theorem. An elementary derivation of the decomposition formula. Transition processes in chains with mutual inductance. Method of reducing to zero initial conditions. Transition processes at jump-like changes of currents in inductance and voltages on capacitors. Non-Linear Circuits . Nonlinear DC Circuits. Magnetic circuits at constant magnetic flux. Direct and Inverse Problems in Magnetic Circuits . The method of piecewise-linear approximation. Straighteners. Method of conditional linearization (method of calculation of transition processes in nonlinear chains) .