MOSFET in Linear or Triode or Ohmic region

See here:. http://everycircuit.com/circuit/6219171353853952

@2ctiby: Thanks, but what I really don't know: what does the MOSFET symbol reflects in EC (the bar/triangle at the gate of the MOSFET). I have created a little test for that: http://everycircuit.com/circuit/5080262192398336 I think, the gate symbol only shows the region in which the MOSFET operates, and the "triangle" does not mean necessarily, that in the circuit the MOSFET is not "fully turne on".

The EC Mosfet settings are very complex. In real Mosfets which we buy, we select one from its data sheet to suit our needs and then use it...there are no settings on it to alter. The EC settings are there so that the Mosfet can be made to work for our individual EC circuit designs which can vary a lot. For instance...in your test example here 10.5v opens the bar fully, but 10.4v on the right only opens it partially. You could either increase the right v, or alter a Mosfet setting instead to get the bar fully open....hence we have the option of different choices to achieve the same end result. My example was to demonstrate the Mosfet settings options for fixed other parameters.

Notice also that you need a resistor in your switched circuit so that infinite current does not attempt to flow. .....and when you put one there, you will see that the 10.4v now opens the bar fully, and even 10v would do so ! ....such is the complexity of these Mosfets, and hence my attempt to demonstrate just one aspect of the settings with a visual wave alteration.

By viewing the action of the wave visually, you can see when no further rise or fall occurs for each setting alteration. I tend to keep away from the words 'saturation' and 'linear' which many use to describe such action...with much confusion partly to do with the words usage for a bjt. In an EC Mosfet when the bar is fully seen, it does not necessarily mean that it is fully saturated with current flow. When it does have the right conditions, then it will be saturated with current and so a graph would then be linear rather than curved.......thus best look at the visual and avoid those terms methinks.

Suitable choice from datasheet, shape of wave correctness and power wastage at the Mosfet should be the basic guide in my opinion for Mosfet usage.