Few years ago, I had downloaded about 4 books named AC, DC, Digital and Semiconductors written by Tony R. Kuphaldt. Those were some of the excellent beginners books I ever found on Electronics. I refer all my students to his books but recently my students complain that those books are not present any more on this site. The topics of the books are present and also the pdfs of all indivisual topics are here. But the whole bundle seems to have disappeared. I had those files but I lost them when I changed my laptop. Can I please get a link to those books?