omer waqar,
A rectifier converts AC current into DC current. As such, it could be considered to be a crude AC to DC converter. However, the term "AC to DC converter" usually refers to a more sophisticated device that also performs such functions as filtering and regulation.
Regards,
Kral
Difference is that rectifier gives you and DC+AC signal, pulsating signal, where DC is bigger than AC. But output DC is not a regulated voltage son DC and AC changes.
AC-DC converters gives at output DC+AC, but DC regulated and AC controlled.