Simulator Directives -- Dot Commands

To run a simulation, not only must the circuit be defined, but also the type of analysis to be performed. There are six different types of analyses: linearized small signal AC, DC sweep, noise, DC operating point, small signal DC transfer function and transient analysis. Precisely one of these six analyses must be specified when you run a simulation.

Whereas the circuit topology is typically schematically drafted, the commands are usually placed on the schematic as text. All such commands start with a period and are called "dot commands".

.AC -- Perform an Small Signal AC Analysis Linearized About the DC Operating Point

.BACKANNO -- Annotate the Subcircuit Pin Names on Port Currents

.DC -- Perform a DC Source Sweep Analysis

.END -- End of Netlist

.ENDS -- End of Subcircuit Definition

.FOUR -- Compute a Fourier Component

.FUNC -- User Defined Functions

.FERRET -- Download a File Given the URL

.GLOBAL -- Declare Global Nodes

.IC -- Set Initial Conditions

.INCLUDE -- Include Another File

.LIB -- Include a Library

.LOADBIAS -- Load a Previously Solved DC Solution

.MACHINE -- Arbitrary State Machine

.MEASURE -- Evaluate User-Defined Electrical Quantities

.MODEL -- Define a SPICE Model

.NET -- Compute Network Parameters in a .AC Analysis

.NODESET -- Supply Hints for Initial DC Solution

.NOISE -- Perform a Noise Analysis

.OP -- Find the DC Operating Point

.OPTIONS -- Set Simulator Options

.PARAM -- User-Defined Parameters

.SAVE -- Limit the Quantity of Saved Data

.SAVEBIAS -- Save Operating Point to Disk

.STEP -- Parameter Sweeps

.SUBCKT -- Define a Subcircuit

.TEMP -- Temperature Sweeps

.TF -- Find the DC Small-Signal Transfer Function

.TRAN -- Do a Nonlinear Transient Analysis

.WAVE -- Write Selected Nodes to a .Wav File