Was looking some software that able to simulate circuit. It should be free program at least and for MS Windows. Google didn’t offer many. Spice (and its analogs) was for Linux/UNIX or was not free. Multisim Electronic Workbench Evaluation Version is for Windows but 160 Mb and I installed it once already. After some search and research I found that I was looking for. It was Quite Universal Circuit Simulator or QUCS. It weight only few Mb and was enough for my educational purposes; after about 40 minutes I can draw circuit and look at signal shape wherever I wanted. I think I will use it in future too.