Hi Hany,
These sites are very good but long text you must be patient read it carefully ask about what you can’t understand:
1) http://www.opamp-electronics.com/tutorials/
2) http://www.kpsec.freeuk.com/analogue.htm
3) http://www.faqs.org/docs/electric/AC/AC_3.html
Please note that you may go to the main page of each site to look at the table of contents and choose subjects or download all and save them for later reading.
You must read all what you find and ask about what you could not understand, be patient this is long text.
Walid.
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