Biasing in MOS Amplifier Circuit MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Biasing in MOS Amplifier Circuit”.

(Q.1-Q.2) A discrete MOSFET common source amplifier has Rin = 2 MΩ, gmm = 4mA/V, ro = 100 kΩ, RD = 10 kΩ, Cgs = 2pF and Cgd = 0.5pF. The amplifier is fed from a voltage source with an internal resistance of 500 kΩ and Is connected to the a load of 10 kΩ.

1. The upper 3-db frequency fH is
a) 11.1 kHz
b) 22.1 kHz
c) 33.1 kHz
d) 44.1 kHz

2. The value of the overall mixed gain AM is
a) -15.2 V/V
b) -16.2 V/V
c) -17.2 V/V
d) -18.2 V/V

(Q.3-Q.4) The amplifier in the figure shown below is biased to operate at ID = 1mA and gm = 1mA/V.


3. Find the midband gain.
a) 0.43 V/V
b) 1.43 V/V
c) 2.43 V/V
d) 3.43 V/V

4. Find the value of CS that places FL at 10Hz
a) 6.57 µF
b) 12.57 µF
c) 18.57 µF
d) 24.57 µF

(Q.5-Q.6) )In the NMOS transistor of the circuit shown below is biased to have gm = 1mA/V and r0 = 100 kΩ.


5. Find fH if Cgs = 1 pF and Cgd = 0.2 pF.
a) 875 kHz
b) 875 kHz
c) 875 kHz
d) 875 kHz

6. Find AM
a) 1.02 V/V
b) 2.04 V/V
c) 3.06 V/V
d) 4.08 V/V

(Q.7-Q.8) For a particular depletion mode NMOS device, Vt = -2V, kn W/L = 200 µA/V2 and λ = 0.02V-1. For VDS = 2V

7. What is the value of the drain current if both L and W are doubled?
a) 408 µA
b) 412 µA
c) 416 µA
d) 420 µA

8. What is the drain current that flows
a) 104 µA
b) 208 µA
c) 312µA
d) 416 µA

(Q.9-Q.10) A depletion type N channel MOSFEt with knW/L = 2 mA/V2 and Vt = 3V has its source and gate grounded. For Vd = 0.1V and neglecting channel length modulating effect

9. In which region is the triode operating?
a) Triode region
b) End of saturation region
c) Saturation region
d) None of the mentioned

10. Find drain current.
a) 1.18 mA
b) 0.89 mA
c) 0.59 mA
d) 0.3 mA

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