LTspice is a freely downloadable spice-based electronic simulator application produced by . Major features include schematic capture (circuit creation), mixed mode simulation, plus the ability to view signals using an integrated waveform viewer.
In addition to its operation as a general purpose simulator, component models are supplied for a wide range of Linear Technology devices including opamps, switched mode power supplies and transistors. Third party models may also be imported, where available.
LTspice IV is is just one of a number of applications and design tools which may be downloaded from the section of their website. A comprehensive range of support resources are available for LTspice from this page, including: