Ctelec Medium
This looks like a GREAT book, it says it’s coming out in August and in PDF form, so should be any moment now?

Essential Electronics for Software Folk: Thinking Inside the Box… Are you a programmer or computer enthusiast? Do you feel comfortable with methods, functions, and variables? Do you wish you knew more about how the computer made it all work? Now you can. From basic electronics to advanced computer hardware, you’ll learn the magic behind the gear that makes it all run. If you’re into tinkering, or ever thought about it, this book explains the basics of how it all works. A lot of people are into Making their own technology these days, from 3D printers to home-made robots, Digital Video Records (DVRs), Media Centers, and more. But it you’re a computer programmer you might not know the ins and outs of the hardware side of these projects.

Essential Electronics for Software Folk – Link.