Seeing startup, switching, or pulse responses. 4. Complete SPICE Example (LTspice Syntax) Circuit: Simple RC low-pass filter with a 10 kHz square wave input.

// Include a model file .INCLUDE my_transistors.lib

LTspice (free, best for beginners), ngspice (open-source), PSpice (commercial), HSPICE (high-precision). 2. The Core Components of a SPICE Netlist A netlist is the text description of your circuit. Every line follows this pattern:

.OP Sweeps frequency, plots gain/phase (Bode plot). Syntax: .AC oct 100 1 1Meg → 100 points/octave from 1 Hz to 1 MHz.

RC Filter Simulation V1 IN 0 PULSE(0 5 0 1n 1n 50u 100u) ; 5V square, 10 kHz R1 IN OUT 1k C1 OUT 0 0.1u