If I may venture to make a suggestion, you should try the MITx online course for circuit design. It's an introductory course with graded homeworks, labs and exams, plus it's free. It's already three weeks in, but the lowest 2 labs and homeworks are dropped (if you even care about that) so it's not too terribly late to join in. I'm taking it now, so I just thought I would suggest it.