# Electronic Devices and Circuits Questions and Answers – MOSFETs Current-Voltage Characteristics

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “MOSFETs Current-Voltage Characteristics”.

1. If a MOSFET is to be used in the making of an amplifier then it must work in
a) Cut-off region
b) Triode region
c) Saturation region
d) Both cut-off and triode region can be used

Explanation: Only in the saturation region a MOSFET can operate as an amplifier.

2. For MOSFET is to be used as a switch then it must operate in
a) Cut-off region
b) Triode region
c) Saturation region
d) Both cut-off and triode region can be used

Explanation: In both regions it can perform the task of a switch.

3. Determine the conditions in which the MOSFET is operating in the triode region from the following figure.
i. VGD > Vt (Threshold voltage)
ii. VDS > VOV
iii. ID ∝ (VOV – 0.5VDS)VDS

a) i, ii, and iii are correct
b) i and iii are correct
c) i and ii are correct
d) ii and iii are correct

Explanation: Only the points I and iii are correct and ii is false.

4. Determine the conditions in which the MOSFET is operating in the saturation region.
i. VGD > Vt (Threshold voltage)
ii. VDS > VOV
iii. ID ∝ (VOV)2

a) i, ii, and iii are correct
b) i and iii are correct
c) i and ii are correct
d) ii and iii are correct

Explanation: i is false and ii and iii are true.

5. In the saturation region of the MOSFET the saturation current is?
a) Independent of the voltage difference between the source and the drain
b) Depends directly on the voltage difference between the source and the drain
c) Depends directly on the overdriving voltage
d) Depends directly on the voltage supplied to the gate terminal

Explanation: Saturation current does not depends on the voltage difference between the source and the drain in the saturation region of a MOSFET.

6. An n-channel MOSFET operating with VOV=0.5V exhibits a linear resistance = 1 kΩ when VDS is very small. What is the value of the device transconductance parameter kn?
a) 2 mA/V2
b) 20 mA/V2
c) 0.2 A/V2
d) 2 A/V2

Explanation: Use the standard mathematical expression to determine the value of kn.

7. An NMOS transistor is operating at the edge of saturation with an overdrive voltage VOV and a drain current ID. If is VOV is doubled, and we must maintain operation at the edge of saturation, what value of drain current results?
a) 0.25ID
b) 0.5ID
c) 2ID
d) 4ID

Explanation: I0 is directly proportional to VOS.

8. Which of the following is true for the triode region?

a) VDG > Vtp
b) VSD < VOV
c) ID ∝ VOV
d) None of the mentioned

Explanation: VDG > |Vtp| and VSD < |VOV|.

9. Which of the following is true for the saturation region?

a) VDG ≤ |Vtp|
b) VSD ≤| VOV|
c) VDG < |Vtp|
d) VSD <| VOV|

Explanation: It is a characteristic for the saturation region.

10. The current iD is?

a) Depends linearly on VOV in the saturation region
b) Depends on the square of VOV in the saturation region
c) Depends inversely on VOV in the triode region
d) None of the mentioned

Explanation: Use the standard mathematical expressions for i0 in different regions.

Sanfoundry Global Education & Learning Series – Electronic Devices and Circuits.

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