What is transistor saturation?

What is the difference between linear and saturation regions in field effect transistor?

• Answer:

  In the linear region, the transistor has an almost linear I versus V curve, which means that as you increase drain-source voltage, current changes proportionally, e.g. to a loose approximation, the FET behaves like a resistor, whose resistance is set by the gate-source voltage. In the saturation region, the I vs V curve looks like a horizontal line (almost) so it acts like more like a switch (neither of these analogies is exact, but they give the general idea).