When MIT ran the first massive online course, 6002x, I found out that MIT 6002x was the electronics course I had wished for back when I was in high school. The high school electronics courses I took only touched upon analysis of the simplest of circuits, and there wasn't a lot of explanation of how the different kinds of transistors (NPN, PNP, MOSFETs..) are modeled.

But oh how much workload the 6002x course was... I needed 10-15 hours per week for all the reading, problems and labs, and doing that while working full time and commuting 2 hours a day was a grueling pace to survive!