MOSFET Amplifier with CS Configuration – 1 MCQ’s

Analog Electronic Circuits Electronics & Communication Engineering

This set of Analog Electronic Circuits Multiple Choice Questions & Answers (MCQs) focuses on “MOSFET Amplifier with CS Configuration – 1″.

1. In the following C.S. stage shown below, what is the transconductance?


a) 12µnCox*(W/L)(V1-Vth)
b) 3µnCox*(W/L)(V1-Vth)
c) µnCox*(W/L)(V1-Vth)
d) 2µnCox*(W/L)(V1-Vth)

2. In the following C.S. stage shown below, what is the input impedance (ideally) if channel length modulation is neglected?


a) Infinite
b) Very high
c) Very low
d) Cannot be determined

3. Neglecting Channel Length Modulation, what is the voltage gain from the gate to the drain of M1?

a) gm * R1
b) gm * 2R1
c) gm * R1 || RO
d) 3gm * R1

4. In the following C.S. stage shown below, what is the input impedance if λ>0?


a) Infinite
b) 0
c) Very low
d) ro

5. In the following C.S. stage shown below, what is the output impedance, if channel length modulation is neglected?


a) 2ro
b) 5
c) R1
d) 0

6. In the following C.S. stage shown below, what is the output impedance if λ>0?


a) ro
b) 0
c) R1
d) R1 || ro

7. In the following C.S. stage shown below, what is the voltage gain from the gate to the drain of M1 if λ>0?


a) gm * ro
b) gm * 2R1
c) gm * R1||ro
d) gm * R1

8. What is the overall input resistance of the CS stage shown below?


a) R3
b) R3 || R1
c) 2 * R3
d) Infinite

9. If the output voltage is sensed at the collector, which of the following option perfectly describes the stage shown below?


a) A degenerated C.S. stage
b) A C.S. stage
c) A shunted C.S. stage
d) An open C.S. stage

10. If the output impedance of the current source is Ri, what is the output impedance of the CS stage shown below, if channel length modulation is neglected?


a) (1 + gm * (R1 || R2)) * Ri + (R1 || R2)
b) {R1 * (R2 + ro)} || Ri
c) R1 || R2
d) 0

11. If both the MOSFET’s are identical, what is the voltage gain from V1 to node S?


a) Vcc – 2R1 * µn Cox * (W/L) * (V1-Vth)2
b) Vcc R1 * 12µn Cox (W/L) * (V1-Vth)2
c) Vcc – R1 * µn Cox (W/L) * (V1-Vth)2
d) Vcc – 4R1 * 12µn Cox * (W/L) * (V1-Vth)2

12. If the transconductance of M1 is 5S, voltage gain for the following degenerated CS stage is _____


a) 2.45
b) 1.25
c) 1.45
d) 2.25

13. If both the MOSFET’s are identical and have channel length modulation, what is the output impedance at node S?


a) R1 || ro1 || ro2
b) R1 + (ro1 || ro2)
c) R1 + (ro1 + ro2)
d) R1 || (ro1 + ro2)

14. If the internal resistance of the current source is finite, what will happen to the voltage gain. for the following C.S. stage, if K is doubled?


a) The voltage gain reduces by 1/2
b) The voltage gain remains the same
c) The voltage gain increases
d) The voltage gain decreases

15. If Channel Length Modulation is present and gm is the transconductance of M1, what happens to the output resistance of for a fixed V2 in the following circuit?


a) (1 + (gm * ro)) * Rs + ro
b) (1 + (gm * ro)) * ro + Rs
c) (ro + 2) * Rs
d) (1 + (gm * ro)) * Rs

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