So I want to discuss a few things about transistors in saturation region. First the saturation part. Lets say the saturation occurs at 0.2 V and transistor cannot go below that voltage. We say that it is bottomed and its now in saturation region. How do charges go from base to collector? Does transistor effect still occur? Let me clarify what I mean. I know when in linear polarization, charges, get injected into base-collector depletion region and get swept across it because of large electric field. (without much discussion, lets say that this the effect) But when we have saturation region, base-collector is directly polarized, and charges don't have that depletion region to get swept across. Do they then, pass over to collector normally like in diodes? I generalized this pnp and npn. You may answer like so, too. Now for the second part, which is closely related. http://pokit.org/get/c4446cd88893f30ed96ced2ec01d0b14.jpg [Broken] I was told that this is input characteristic of a BJT. I believe these curves represent the diode characteristic of base-emitter. I want to discuss the difference between 2 curves, when transistor is in linear and saturation region. My explanation of the curves is: When transistor is in saturation region, base only has depletion region from emitter-base junction. And indeed, this part really acts like a diode, and will have that characteristic. Peaks out at 0.7 V But when transistor is in linear region, we have that depletion region from collector-base too. So base is being "squished" between 2 depletion regions. Because of this, we will need a larger voltage drop, to achieve the same current as in saturation region case. In a nutshell, base "offers" smaller path for current to go through and ergo we need more voltage to get more current? Am I thinking right here?