Assume a student measured the collector current in a saturat

Assume a student measured the collector current in a saturated transistor as 10 mA and the base current as 0.25 mA. Why can\'t these measurements be used to determine the szlig_DC of the transistor?

Solution

1)we know that Ic=BdcIb ,since before transistor goes to saturation collector current is propositional to base current.

2)let Ib(min) is the base current at which collector current Ic goes from edge of active to saturation region.

3)At this Ib(min) collector current be Ic(sat),so Bdc=(Ib(min)/Ic(sat)).

4)When Ib((min) < Ib ,even then Ic= Ic(sat), so we say Ib is over driven.so at this case Bdc=~(Ib/Ic),since Bdc becomes more than actual .

5)so Bdc has to find only in active region.