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Advanced Electronic Devices and Circuits Questions 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 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
3. 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
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 loaC.
A. 3.25 v/V
B. 6.5 V/V
C. 9.75 V/V
D. 13 V/V
5. 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
6. 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
(Q.7-Q.8) The NMOS transistor in source follower circuit shown has gm = 5mA/V and a large r0 .
7. Find the output resistance.
A. 0.1 kΩ
B. 0.2 kΩ
C. 0.3 kΩ
D. 0.4 kΩ
8. Find the open-Circuit voltage gain.
A. 1 V/V
B. 2 V/V
C. 3 V/V
D. 4 V/V
Answer: A
9. 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
10. 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