Transient analysis is an extension of DC analysis to the time domain. A transient analysis begins by obtaining a DC solution to provide a point of departure for simulating time-varying behavior. Once the DC solution is obtained, the time-dependent aspects of the system are reintroduced, and the two simulator algorithms incrementally solve for the time varying behavior of the entire system. Inconsistencies in node values are resolved by the two simulation algorithms such that the time-dependent waveforms created by the analysis are consistent across the entire simulated time interval. Resulting time-varying descriptions of node behavior for the specified time interval are accessible to you.

All sources that are not time dependent (for example, power supplies) are set to their dc value. The transient time interval is specified on a .TRAN control line.