introduction provides an easy to understand explanation of what gates
are and how they can be connected together in various ways to produce
more complicated behaviors.
"Clocked Logic" Tutorial explains the various flip flops and the
difference between level and edge clocked circuit, using lots of images
and simulations along the way.
TUTORIAL: Very important!! A strong foundation in binary will help you
learn the principals of digital electronics much faster. This tutorial
is very easy to learn and includes a simulation and examples.