http://www.electronicapt.com/forum/esquemas-b12.0/
http://www.uoguelph.ca/~antoon/circ/circuits.htm
http://amsfrancisco.planetaclix.pt/textos.htm
http://www.vabsco.com/bardhp/
http://sdig.home.sapo.pt/Links_Electrotecnia/d_electrotecnia.htm
http://electronred.iespana.es/index.htm
http://electronicos.planetaclix.pt/esquemasdiversos2.htm
http://www.miniplanes.net/electronica1.htm
http://www.prof2000.pt/users/lpa/texto_apoio_ep.html
http://www.pablin.com.ar/electron/circuito/computer/index.htm
http://www.electronicafacil.net/
http://www.comunidadelectronicos.com/sitios2.htm#Manuales
http://www.uoguelph.ca/~antoon/circ/circuits.htm
http://amsfrancisco.planetaclix.pt/textos.htm
http://www.vabsco.com/bardhp/
http://sdig.home.sapo.pt/Links_Electrotecnia/d_electrotecnia.htm
http://electronred.iespana.es/index.htm
http://electronicos.planetaclix.pt/esquemasdiversos2.htm
http://www.miniplanes.net/electronica1.htm
http://www.prof2000.pt/users/lpa/texto_apoio_ep.html
http://www.pablin.com.ar/electron/circuito/computer/index.htm
http://www.electronicafacil.net/
http://www.comunidadelectronicos.com/sitios2.htm#Manuales
Nos comentários puderam adicionar mais link’s.