I word about terminology.

In a MOSFET, the "linear" region is the triode region in which the current is linearly-dependent on the drain-source voltage, making it act like a resistor whose value is controlled by the gate-source voltage. It's the saturation region where the drain-source current is largely independent of gate-source voltage. This is very different from a BJT in which the "linear" region is the region in which the collector current is linearly-dependent on the base current. The word that applies to both when describing its use in something like an analog amplifier is that they are operating in the "active" region.

 

I word about terminology.

In a MOSFET, the "linear" region is the triode region in which the current is linearly-dependent on the drain-source voltage, making it act like a resistor whose value is controlled by the gate-source voltage. It's the saturation region where the drain-source current is largely independent of gate-source voltage. This is very different from a BJT in which the "linear" region is the region in which the collector current is linearly-dependent on the base current. The word that applies to both when describing its use in something like an analog amplifier is that they are operating in the "active" region.

Always good to remember people about this. I never found a single soul that understood this simple thing that switch places from MOSFET to BJT. It's probably world wide like that.

 

Always good to remember people about this. I never found a single soul that understood this simple thing that switch places from MOSFET to BJT. It's probably world wide like that.

It is -- and I know I tend to think the same way. It's pretty natural because if we bias a transistor so that it operates the way we want in a linear circuit, it's only natural to think that the device must be operating in a linear mode. But the term "linear" in this case is just referring to a region of operation in which one parameter has a (nominally) linear mathematical relationship to another parameter. Similarly, "saturation" is referring to a physical phenomenon within the device, but this happens in two very different regions of operation between the two types of transistors. We can use the single terms "cutoff", "active" and "resistive" for the corresponding regions of operation.

 

Perhaps these two diagrams will help in reducing the confusion between the names of the operating states for a BJT (top diagram) and a MOSFET (bottom diagram):

I think the people who named those operating regions differently from how an engineer would name them, were having some fun at our expense.

BJT--

MOSFET--

 

Perhaps these two diagrams will help in reducing the confusion between the names of the operating states for a BJT (top diagram) and a MOSFET (bottom diagram):

I think the people who named those operating regions differently from how an engineer would name them, was having some fun at our expense.

BJT--
View attachment 371014
MOSFET--
View attachment 371016

One region that is compressed into a line is the cutoff region. It's a region governed by the exponential subthreshold (Vgs < Vth). Also the Vth changes based on a non-intuitive function when the body voltage is not the same as the source voltage.
There, all the quirks of the MOSFET. (Channel-length modulation can be inferred by your graph).

 

I don't mean anything by it, I just prefer you guys to answer yes or no to keep it brief.

 

I don't mean anything by it, I just prefer you guys to answer yes or no to keep it brief.

So you aren't interested in the "why"?

 

So you aren't interested in the "why"?

I also want to know why, but I feel shy when I ask too many questions.

 

I also want to know why, but I feel shy when I ask too many questions.

Just to clarify, the reason this place was created in the first place is for people to ask questions and getting proper guidance in their search for answers. The only thing expected from those that ask the questions is for them to show that they're truly trying to learn.

 

Just to clarify, the reason this place was created in the first place is for people to ask questions and getting proper guidance in their search for answers. The only thing expected from those that ask the questions is for them to show that they're truly trying to learn.

I understand. Thanks.

 

Why this continuing obsession about whether a device is in the "linear" region?

Because the meaning is practically opposite for BJTs vs MOSFETs.