Example Problems: Identify the mode (7-Transistors)

Is the transistor forward active, cutoff, saturation, or reverse active? And is the base current negligible? Let's work several examples together.
Aaron Danner is a professor in the Department of Electrical and Computer Engineering at the National University of Singapore.
danner.group
Video filmed and edited by Cheryl Lim.
@randomcheryl

[@amazagx]

Puff!! This is great!! Thank you very much!!
You are really good teaching! 👍🙏

[@andymouse]

Solid gold tutorial....cheers!!

[@e74av]

quick tips and tricks : )

[@SergiuCosminViorel]

eye watering! thanks!
it comes like some answer to my post under the previous video.
well, it does not answer my problem.
why do i find bipolar transistors that have specified Vce-sat less than 0.6V ?
i understand that the saturation mode means something else, but why Vce-sat in catalogs sometimes so small?
i thought myself an explanation, but am not sure...
is it about better linearity at lower voltages?
adding some more, as another idea came to me:
the transistor, when Vce=Vbe, is no longer the two diode model. if it ever was.
when Vce=Vbe, must consider both directions for the curent between base and colector.
leave aside the way of thinking electronics!
there are two curents, both directions. think like thermal, do not think like electronics!
Ice is still bigger than Ibe, and it is not estinguished instantly, therefore it is possible for Vc to be lower than Vb (npn transistor), and for certain types of transistors, it may go much under, and that can still be the active mode. the base-colector junction does not behave like a diode. it does not open when it has a direct voltage Vbe. it does not open abruptly, like a diode, it just sums the two curents, going toward some equilibrium.