Multisim is a very useful and powerful SPICE software designed by National Instruments that can be used to design and simulate electronic and electrical circuits .
Multisim is a very complex easy to use simulation software that can be used for small ( low complex ) and huge complex electronic circuits .
Multisim SPICE software is not free but is very nice , the main menu is arranged in some way that helps you to design and simulate very quickly and easy any circuit .
Zenit PCB is another useful software that can help you to design printed circuit boards . Zenit PCB is designed by Stortini Mirko Bruno and is completely freeware for personal or semi-professional use, limited to 800 pins . Zenit PCB is a flexible easy to use CAD program, which allow you to realize your projects in a short time . Zenit PCB has three main parts : Zenit PCB , Zenit Capture and Zenit Parts .
PCB123 is a printed circuit board design software provided and designed by Sunstone and it can be used for free .
In the old version PCB123 has contained two part one for circuit drawing and other part for printed circuit board design , in the actual version you have both : circuit editor and pcb editor .