A free app for Android, by ирина данилова.

This is an application that allows you to read all the information you need to know in order to get a good understanding of the world of electronics and how it works. 

There is a lot of information in this application and the best part is that it is all presented in an easy-to-understand and very interactive way. It is a book for beginners and intermediate students of electronics, so if you have no prior knowledge of electronics or if you want to refresh your knowledge, this is the best app for you. 

There are a lot of illustrations and simple explanations available to a beginner, which makes her the best tutorial on electronics.