Computer Programs to help design circuits to hook up to a Raspberry Pi

[Borg]

I would like to start building small electrical projects but it's been a very long time since I studied circuit analysis in college. I figured that there are probably some computer programs that would help people like myself to design simple circuits. A quick Google search led me to this site - The Top 50 Tools for an Electrical Engineer’s Toolbox. There are a lot of links to various programs there and I was wondering if anyone has had any experience with any of those or can recommend something that is either free or relatively cheap. Thanks for your replies.

BTW, the projects that I'm referring to are circuits that I could hook up to a Raspberry Pi to control various devices and switches.

 

[Baluncore]

Free. LTspice. http://www.linear.com/designtools/software/

 

[Nidum]

https://www.circuitlab.com/

 

[nsaspook]

http://www.autodesk.com/products/eagle/overview