Quadcept allows the user to generate a netlist for the SPICE simulator and run a simulation with LTspice without having to rewrite your circuit design for simulation.
Perform a non-linear, time-domain simulation.
Compute the small signal AC behavior of the circuit linearized about its DC operating point.
Compute the DC operating point of a circuit while stepping in dependent sources and treating capacitances as open circuits and inductances as short circuits.
Perform a stochastic noise analysis of the circuit linearized about its DC operating point.
Find the DC small-signal transfer function.
Compute the DC operating point treating capacitances as open circuits and inductances as short circuits.
You need to download LTspice separately.
LTspice allows you to simulate various types of circuits, but there may be some differences between the simulated and actual behavior because each simulation model uses standard values for each parameter. Please note this when you run simulations.