# MOSFETs Circuits at DC MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “MOSFETs Circuits at DC”.

1. The PMOS transistor in the circuit shown has V_{t} = −0.7 V, μ_{p}C_{ox} = 60 μA/V^{2}, L = 0.8 μm, and λ = 0. Find the value of R in order to establish a drain current of 0.115 mA and a voltage V_{D} of 3.5 V.

a) 12.5 KΩ

b) 25 kΩ

c) 37.5 kΩ

d) 50 kΩ

2. The MOSFET shown has Vt = 1V, k_{n} = 100µA/V^{2} and λ = 0. Find the required values of W/L and of R so that when v_{I} = V_{DD} = +5 V, r_{DS} = 50 Ω, and V_{O} = 50 mV.

a) W/L = 25 and R = 4.95 kΩ

b) W/L = 25 and R = 9.90 kΩ

c) W/L = 50 and R = 4.95 kΩ

d) W/L = 50 and R = 9.90 kΩ

3. The transistor in the circuit shown below has k_{n} = 0.4 mA/V^{2}, V_{t} = 0.5 V and λ = 0. Operation at the edge of saturation is obtained when

a) (W/L)R_{D} = 0.5 kΩ

b) (W/L)R_{D} = 1.0 kΩ

c) (W/L)R_{D} = 1.5 kΩ

d) (W/L)R_{D} = 2.0 kΩ

4. The NMOS transistors in the circuit shown have V_{t} = 1 V, μ_{n}C_{OX} = 120 μA/V^{2}, λ = 0, and L_{1} = L_{2} = L_{3} = 1μm. Then which of the following is not the value of the width of these MOSFETs shown

a) 2 µm

b) 8µm

c) All of the mentioned

d) None of the mentioned

(Q.5-Q.7) For each of the circuits shown find the labeled voltages. For all transistors, k_{n}(W/L) = 1 mA/V2, V_{t} = 2V, and λ = 0

5. Find V_{3}

a) 2.41V

b) 3.41V

c) 4.41V

d) 1.41V

6. Find V_{1} and V_{2}

a) 2V and -4V

b) -2V and 4V

c) 2V and 4V

d) -2V and -4V

a) 4V and -5V respectively

b) -4V and 5V respectively

c) 4V and 5V respectively

d) -4V and -5V respectively

(Q.8 & Q.9) For each of the circuits shown find the labeled node voltages. The NMOS transistors have V_{t} = 1 V and k_{n}( W/L ) = 2 mA/V_{2} and λ = 0

a) 3.775V and 5V

b) 3.775V and 2.55V

c) 7.55V and 2.55V

d) 7.555V and 5V

9. For the PMOS transistor in the circuit shown k_{n}= 8 µA/V^{2}, W/L = 25,|V_{tp}| = 1V and I = 100μA. For what value of R is V_{SD} = V_{SG}?

a) 0 Ω

b) 12.45 kΩ

c) 25.9 kΩ

d) 38.35 kΩ

a) 2.44 and -1.28 V

b) 2.44 and -2.56 V

c) 1.22 and -2.56 V

d) 1.22 and -1.28 V

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