Embedded Cookbook - A community for electronic developers and the tools to share information about electronic parts. A list of available datasheets and a forum. - http://embeddedcookbook.com/
Alldatasheet - Free datasheet archive and search for electronic components and semiconductors. - http://www.alldatasheet.com/
GlobalSpec Datasheet Directory - Directory and search of data sheets on electronics components and other technical products; index of component manufacturers. - http://www.globalspec.com/datasheets/
Electronic Engineers Master - An online edition of EEM- catalog of electronic components, equipment and services with links to the manufacturers as well as reference designs and application materials. Requires registration. - http://www.eem.com/
Allegro Technical Publications - Technical publications and application notes on step motor drive technology, power conversion and semiconductors. - http://www.allegromicro.com/en/Products/Design/Tech_Pubs.asp
Spread Spectrum Scene Online - A collection of RF related application notes and reference materials. - http://sss-mag.com/
DataSheet4U - Free datasheet archive and search. - http://www.datasheet4u.net/
Jaycar Electronics Primers - Data, information pages and application notes on using batteries and other electronic components. - http://www1.jaycar.com.au/primers.asp
Fluke Application Notes - Application Notes from Fluke on electronic, electrical, predictive maintenance and biomedical measurements. - http://us.fluke.com/usen/support/appnotes/default.htm
USB 2.0 Documentation - The original and all subsequent specifications including errata sheets and class documents. - http://www.usb.org/developers/docs/
Manufacturers of Support Components - A list of manufacturers of various types of electronics components compiled by Maxim. Manufacturers will sell in small quantities to experimenters. - http://www.maxim-ic.com/TechSupport/manufacturers.htm
MAGNETICS Digital Library - Ferrite and powder core literature, newsletter archive. - http://www.mag-inc.com/library.asp
Magnet web - Directory of magnet suppliers, design of permanent magnets, technical documents related to magnetic fields. - http://magnetweb.com/
Intel MCS 51-251 Microcontrollers - Intel's 8-bit MCS® 51 family of microcontrollers development site. Technical documents, support, FAQ. - http://developer.intel.com/design/mcs51/cf_51.htm
Datasheet Archive - Provides searchable database of electronic component datasheets and data books. Allows browsing and includes photographs. - http://www.datasheetarchive.com/
Avtech Applications Information - Application notes and technical briefs on pulse generators, laser diode drivers, function generators, and amplifiers. - http://www.avtechpulse.com/appnote/
Electronics-OEM - A listing of electronics companies, semiconductors, chips, discretes, passives and actice componenets. - http://www.electronics-oems.com/
Parallel Port Standard Information - A detailed technical introduction to the IEEE 1284 parallel port. - http://www.fapo.com/ieee1284.htm
Micro Electronics Ltd- Datasheets - Transistors, displays, LEDs, Voltage regulators and other. - http://www.microelectr.com.hk/datasheet.asp
Semiconductor Datasheets - An index of manufacturers and data sheets for chips, transistors, diodes and more. - http://sdw.bgs.nu/
GE Power Management - Application notes on power systems. - http://pm.geindustrial.com/faq/Faq.asp
Electronic Component Datasheets - Data sheets of electronic components and a list of application notes. - http://www.ife.tugraz.at/datashts/
Global Electronic Components Datasheet Locator - A free electronic engineering tool that will enable the user to locate product datasheets from hundreds of electronic component manufacturers worldwide. - http://www.datasheetlocator.com/
Application Notes - Application notes from Maxim: A/D and D/A, audio, measurement and other circuits. - http://www.maxim-ic.com/appnotes10.cfm/filter/category
Application Notes from Rohde and Schwarz - Alphabetical and search lookup for application notes on radiocommunications, broadcasting, test and measurements, and more. - http://www.rohde-schwarz.com/www/dev_center.nsf/dynframe?OpenAgent&navig=/www/dev_center.nsf/html/nav,10,11&content=/www/dev_center.nsf/appnotes?OpenFrameset
ZiLOG - Application notes on the Z8 series Microcontrollers. - http://www.zilog.com/products/appnotes.asp
Microsemi Co - Mostly discrete semiconductors application notes. - http://www.microsemi.com/support/micnotes.asp?MN=316
Beldon Cable College - Technical papers, applications notes and product reports for various types of coax-cable. - http://bwcecom.belden.com/college/college.htm
Technical Articles AVX Online - Technical articles and application notes on capacitors, ceramic resonators, and other passive components. - http://www.avxcorp.com/TechInfo_catlisting.asp
TestMart - Application notes, product tutorials, buying guides, from many test and measurement manufacturers - http://www.testmart.com/applicationnotes/appnotestmp.cfm
NTE - Semiconductor cross reference search. One of the most extensive cross reference guides on the net. - http://www.nteinc.com/cgi-bin/nte.pl
555 Timer - Applications of the most common IC timer chip. - http://www.ee.ed.ac.uk/~kap/Hard/555/aplications.html
Fairchild Semiconductor Application Notes - Application notes and other documents on analog, mixed signal, interface, logic and other ICs, as well as discrete semiconductors. - http://www.fairchildsemi.com/apnotes/
ST Bookshop - A great little resource for various application notes and data sheets, replacement guides are included. - http://www.st.com/stonline/books/
National Semiconductor Application Notes - National Semiconductor application notes: analog, mixed signal, power, data converters, and more. - http://www.national.com/apnotes/