The circuit introduced on this page is a circuit which controls a thyristor by software of PIC. It is also possible to make control the electric bulb on a Christmas tree bright gradually and dark gradually. Blink control of various patterns can be performed.
http://www.hobby-elec.org/e_pic6_c.htm
This is a light controller built using PIC16F873. This circuit is usable only in the direct electric current.
http://www.hobby-elec.org/e_pic6_5.htm
dim 115V lights up to about 350 watt
http://www.aaroncake.net/circuits/dimmer.htm
control the current in a cold-cathode fluorescent tube (CCFT) and, hence, its brightness with a switching-regulator IC
http://www.edn.com/archives/1995/021695/04di1.htm
http://www.edn.com/archives/1998/061898/13di.htm
basic dimmer circuit for 220V AC
http://www.saburchill.com/tech/electronics/elect041.html
http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#pumpkin.gif
dim lights up to about 350 watts of 110V AC lighting
http://www.uco.es/~p62fugoj/dimmer.htm