Here are some electronics designs I made and built. If you spot errors or potential improvements, please let me know.
A simple step-up converter (6V to 12V @ 1A).
A small FM transmitter.
Knight Rider lights for model cars.
Solar lead-acid battery charger.
Using a solar panel for USB charging.
Emergency USB charger.
Semi-serious battery light.
Playing with an Arduino and sensors.
USB charging away from the mains.
(Try Arian van Dorsten's projects page, Tomi Engdahl's electronics page or Hack a Day for more designs and information.)
by Horowitz and Hill.Good for studying or looking things up, full of examples on how-to (and how-not-to 8-), not overly theoretical, complete and thorough, aimed at designing rather than analysis. The best general-purpose book on the subject I have found so far, and fun to read too.
by Louis E. Frenzel, Jr.What it says: a crash course in the basic theory of electronics using programmed instruction, a good book to learn the basics quickly. My copy is quite old and from Sams publishers, I don't know if the book has changed much since.
by Millman and Grabel.A friend of mine (who designs electronics for a living) loves this book: thorough explanations, practical, plenty of examples, but not for beginners.