Free eBooks
There are some sites apart from freeonlinebooks.co.in which has the nice resources of free online books and eBooks. You can also refer this sites for books.
Free Textbooks: This site freeonlinebookstore.org contain free textbooks and free books in more than 15 categories which include science books, mathematics, history , war and other books. You can get engineering books also on this site.
Free pdf books: This site getfreepdf.com has most of the books in pdf format which can be easily downloaded. They have a small number of ebooks but some of the ebooks are useful.
Download free technical Books: This site getfreebooks.net contains mostly technical books on computer and electronics. Computer books includes programming books and from computer science background.Amplifier, Circuits,DSP,Verilog books can be founded under electronics section.