The history of transient analysis and the recent trend

The paper has summarized the history of a transient analysis including the impedance necessary for the analysis, and various problems associated with transient simulations are pointed out. Existing simulation tools based on a circuit theory still require refinement to improve the accuracy and the reliability at the same time. The tools inherently necessitate circuit parameters which involve a number of problems due to the assumption and the limit when the parameters were derived. A numerical electromagnetic analysis method looks quite promising as a transient simulation tool, because it is able to solve any transients which can not be dealt with by a circuit‐theory based tool. One of the main features of the method is that it does not require circuit parameters for those are automatically calculated as a part of a transient simulation.