Uses standard spice simulators for doing loadflowanalysis in the high energy domain. Intended for didactical purposes.
http://members.aon.at/fschmid7
Basics, hints and precautions, links to many informative sites.
http://www.misty.com/~don/donflash.html
Reference materials and tutorials on frequency control, quartz crystal resonators and oscillators, piezoelectric sensors, and timekeeping.
http://www.ieee-uffc.org/index.asp?page=freqcontrol/fc_reference.html&Part=5#tutor
Operational Amplifiers Use & Operation
http://www.williamson-labs.com/480_opam.htm
basics in a text file.
http://www.altair.org/projects/TCBasics.txt
for op amp.
http://margo.student.utwente.nl/el/analog/opamp03.gif
Shows design procedure and implementation of an active band-pass filter.
http://ite.gmu.edu/~aaljassa/ece464/project.html
Quite a bit of theory, practical advice, math and diagrams, from bacic electronics theory to very advanced physics.
http://www.ee.surrey.ac.uk/Workshop/index.html