Discrete-Circuit MOS Amplifiers MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Discrete-Circuit MOS Amplifiers”.

1. Calculate the overall voltage gain Gv of a common source amplifier for which gm = 2mA/V, RD = 10 kΩ, R0 = 10 kΩ and RG = 10 MΩ. The amplifier is fed from a signal source of Thevenin resistance of 0.5MΩ and the amplifier is coupled with a load of 10 kΩ.
a) -11.2 V/V
b) -22.4 V/V
c) -33.6 V/V
d) -44.8 V/V

(Q.2-Q.6) The MOSFEt circuit below has Vt = 1V, knW/L = 0.8 mA/V2 and VA = 40V


2. Find the value of gm at the bias point
a) 0.1 mA/V
b) 0.2 mA/V
c) .0.3 mA/V
d) 0.4 mA/V

3. Find the value of RG so that iD = 0.1 mA, the largest possible value of RD is used while the maximum signal swing at the drain is of 1V and the input resistance at the gate is 10 MΩ.
a) 1 MΩ
b) 10 MΩ
c) 0.1 MΩ
d) 0.01 MΩ

4. If terminal Z is grounded, X is connected to a signal source having a resistance of 1 MΩ and terminal Y is connected to a load resistance of 40 kΩ, find the voltage gain from the signal source to the load.
a) 3.25 v/V
b) 6.5 V/V
c) 9.75 V/V
d) 13 V/V

5. If terminal X is grounded and terminal Z is connected to a current source delivering a current of 10 µA and having a resistance of 100 kΩ, find the voltage signal that can be measured at Y neglecting the effect of V0 .
a) 0.34V
b) 0.68 V
c) 3.4 V
d) 6.8 V

6. If terminal Y is grounded find the voltage gain from X to Z with Z open-circuit.
a) 0.33 V/V
b) 0.66 V/V
c) 0.99 V/V
d) None of the mentioned

(Q.7-Q.8) The NMOS transistor in source follower circuit shown has gm = 5mA/V and a large r0 .


7. Find the open-Circuit voltage gain.
a) 1 V/V
b) 2 V/V
c) 3 V/V
d) 4 V/V

8. Find the output resistance.
a) 0.1 kΩ
b) 0.2 kΩ
c) 0.3 kΩ
d) 0.4 kΩ

9. If the output of the source follower in (I) is connected to the input of the common gate amplifier of (II). Determine the overall voltage gain (V0 /Vi ).


a) 1.55 V/V
b) 3.55 V/V
c) 5.55 V/V
d) 7.55 V/V

10. The NMOS transistor in the common gate amplifier as shown in the circuit below has gm = 5 mA/V. Find the input resistance and the voltage gain.


a) Input resistance: 0.1 kΩ and Voltage gain: 3.05 V/V
b) Input resistance: 0.1 kΩ and Voltage gain: 3.05 V/V
c) Input resistance: 0.2 kΩ and Voltage gain: 3.05 V/V
d) Input resistance: 0.2 kΩ and Voltage gain: 7.1 V/V

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