Learn Online?

Sure you have heard that before. Read books, read tutorials, howtos, but there's a catch, like always. Pay X$ get limited access for X period. Did ja ever find anything free? Bah humbug, you say.

But you did, you just weren't looking. It's high time you realised that google is your friend and it wants to help you. That is why you can find free tutorials and howtos on practically everything, not just on computers, linux, web designing, but even maths, physics and chemistry.

sosmath.com

allaboutcircuits

chemhelper.com

These links adhere to my belief. There is lots to read online, if you can only identify what serves your purpose. If you need to study about rectifiers, you'd probably start by looking for books. Had you just searched for rectifiers(half, full) on google, you would've come across several interesting web pages.

All the stuff is already here. It's always been, and I think it's about time you started using it for your own good.

Happy surfing and happy learning :)