Hello IjaP 1012
There are many e-books available for Electrical and Computer Engineering (ECE) students. The "best" one depends on your specific needs and interests within the field..
however still you can try both of these books. These provide a comprehensie knowledge to ECE Students.
Microelectronic Circuits" by Adel S. Sedra and Kenneth C. Smith: A comprehensive resource on analog electronics and microelectronics.
Introduction to the Theory of Computation" by Michael Sipser: An essential book for understanding the theory of computation and algorithms.