I want an alternative to Crocodile Clips 3.5, the educational electric simulator. I already know Yenka but I'm looking for something different. It would be better if the program is open source and...

I want an alternative to Crocodile Clips 3.5, the educational electric simulator. I already know Yenka but I'm looking for something different. It would be better if the program is open source and runs on Ubuntu. EDIT: Requeriments: Do basic electric and electronic simulation Free for personal use Run on Ubuntu Optional: Open source Posibility to add more components