All of us know that NE555(or other versions) is a versatile IC for building big and small projects. Recently, I found some free simulators that would be very useful for electronics beginners. Please go the links I have given on this page and download those applications for FREE. You may also find something more useful on those pages. I will update this page again once I find more simulators. Please write me if you know any.
CLARKSON: Clarkson offers a FREE 555 timer simulator for you. On this site, you can read about different modes of 555 timer and get some interesting projects also. It offers both online and installable simulators.
YENKA: YENKA is educational modelling tool from Crocodile Clips. It is one of the best learning and teaching tools for teachers and students. With YENKA, you can simulate simple electronic projects. It offers 150 types of components, PCB designing, PIC programming and experiments with a range of mechanical input and outputs, in full 3D. You can get a FREE copy of YENKA.