Question

The regions of operation of a MOSFET to work as a linear resistor and linear amplifier are:
1. Cut-off and saturation respectively
2. Triode and Cut-off respectively
3. Triode and saturation respectively
4. Saturation and Triode respectively 

Answer 1

Correct Answer - Option 3 : Triode and saturation respectively

• A channel is created when the voltage between gate and source terminals V_GS is greater than the threshold voltage V_TH
• When V_GS > V_TH, the device is said to be in a triode (or constant resistance) region or saturation region depending on the voltage across drain and source terminals V_DS.
• For any V_GS, if V_DS < V_TH then the device is in triode region (also known as constant resistance or linear region)
• If V_DS > V_GS – V_TH, then the device enters into a saturation region.
• When V_GS < V_TH, then the device is in OFF state. The gate current in other regions of operation is very less (almost equal to zero)

 

Therefore, MOSFET is known as voltage-driven device.