There are many free circuit simulation software,it would be very huge to list all kinds of software.I think it maybe good to have a place for people to share a free and useful software。
I have tried EasyEDA, I think EasyEDA is the just software which I try to find .
I thought people might be interested in EasyEDA for the following reasons.
ii) work can be shared and - with a bit of agreement on who saves what, when via a 3rd party instant messaging service - it supports collaboration;
iii) it has some pretty impressive import and export options such as importing Altium, Eagle and LTspice files and exporting spice netlists and svg, png and pdf files for documentation. It also uses open standard JSON format files internally so it's easy to do some quite whizzy things just using a text editor;
iv) all use of the tool is free even to the point where the user can download PCB Gerbers and send them off to any PCB supplier;
v) it also offers a low cost PCB service: PCBs can be ordered directly from within the tool (this seems to be the way the money is made to keep the whole thing afloat);
vi) it can even be used without registering with files being saved in an Anonymous mode that works a bit like pastebin where files can be retrieved and shared just by their urls.
Of course, then we would never pay for the good stuff that works and has lots of features we can never understand because we can't attend the suppliers training program. Mentor does have online training and I have watched the videos over and over. They are still lacking.