TRAN: a program for the transient analysis of circuits

The application of computers to circuit design is discussed, with particular emphasis on the analysis of nonlinear circuits in the time domain. Circuit modelling and numerical integration are considered in detail. It is concluded that it is better to use only basic elements and to build up more complicated devices (e.g. transistors) from these. The most suitable integration formula is the trapezoidal rule, provided that a suitable method of time-step adjustment is used. The choice of time step may be based on the estimation of the local truncation error, or on a comparison of the results computed with different step lengths. For nonlinear circuits, the latter method has been found to be superior. A computer program, TRAN, based on these conclusions, has been written in ASA FORTRAN. It is suitable for use on a time-sharing system or a minicomputer, and has been used on a wide range of problems. Several examples of its use are given.