This site provides a series of online textbooks covering electricity and electronics. The information provided is great for both students and hobbyists who are looking to expand their knowledge in this field. These textbooks were written by Tony R. Kuphaldt and released under the Design Science License.
Thanks to a contribution to AAC from Tim Fiegenbaum, we have over 100 Video Lectures based on the textbook "Electronics for Computer Technology". These video lectures cover many of the topics contained within the textbooks, and are an excellent supplement to reinforce concepts.
The tools section features dozens of useful electrical engineering calculators, complete with detailed explanations and diagrams about their calculations and applications.