.TR Record

This record requests a time domain or TRansient analysis of the circuit. The '.' before TR must be in the first column of the record. The .TR record contains three parameters which control the analysis:

.TR I1, F1, F2

where

• [I1] integer number of time steps to be calculated.
• [F1] real, the analysis starting time.
• [F2] real, the analysis end time.

The transient analysis always starts at time = 0.0 with the first response calculated for time = (F2 - F1) / I1. Only the data generated after time $\geq$F1 is written to output file(s).

The number of time intervals refers to the number of intervals calculated between the start and end times. The calculation time step will be (F2 - F1) / I1. This time step will be used before F1 if F1 > 0.0.

Examples:

.TRAN 100 0.0 1.0 * 100 steps from 0 to 1 second.

.TRAN 500 5.e-9 20.nsec * 500 intervals from 5 to 20 nsec.

The TRansient analysis will produce the step response for the specified circuit unless an impulse response is requested on the .OPT record.