(1) Williamson labs.
it has collection of more than 400 urls in over 90 related subject areas. this website helps you to understand and imagine electronics with the help of animations and 3D pictures.
(2) electronics tutorials.
offering free,comprehensive basic electronics tutorials in amplifiers,antennae,filters,oscillators,power supplies,receivers,radio and electronics designes. it covers over 120 individual topics with links to datasheets,reference books and projects.
(3) raspberry pi tutorials.
this website offers free,comprehensive raspberry pi tutorials. helps you to program your device . tutorials are targeted at anyone who can read and has access to a computer programming language python.
this website is dedicated to the MCS51 microcontroller and related products. it includes the traditional 8052,8051,8032,8031 along with more modern derivatives such as the Atmel AT89S8252, andmany derivatives by silicon laboratives,philips and others.