while drawing the dc load line , , we take VCE = 0 and mark it as saturation point but but in saturation state VCE is very small but not zero..!! I actually want to make clear that whether its a fact or is it just an assumption to find out saturation point..?? similarly for the cutoff point we take IC=0 !!..Please explain this thing!! Also , we define operating point as a point on the dc load line which represents VCE & Ic in ABSENCE OF SIGNAL... this thing I wanted to ask that what does it mean by having no signal..?? Does it mean no input..?? & why we are defininf it for no signal..??