hai to every one,,
Could anyone help me with a circuit diagram for SMPS with a specification of 600watts,(230v ac to 120v dc).

 

well, all i can tell u is that the simplest way is to use a buck converter after the rectifier.
simple, cheap, reliable, efficient.

 

There are tons of cheap ready made SMPS available.

Try a google for "600W 120VDC SMPS".

 

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGLR_enUS318US212&q=600W+120VDC+SMPS