Analog Circuits Practice Test 9

1. 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?

{R₁ * (R₂ + r_o)} || R_i

(1 + g_m * (R₁ || R₂)) * R_i + (R₁ || R₂)

R₁ || R₂

2. What is the input impedance for the following circuit?

r_o

Infinite

R_d || r_o

1/g_m

3. Given that the feedback factor of an astable multivibrator is 0.3, find the frequency of the output.

22Hz

20Hz

40Hz

20kHz

4. The follower stage is mostly used as a ____________

Amplifier

Buffer stage

Current source

Switch

5. 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?

The voltage gain remains the same

The voltage gain decreases

The voltage gain increases

The voltage gain reduces by 1/2

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

R₁

2r_o

7. If g is the transconductance and r is the resistance due to channel length modulation - what is the total voltage gain if both M₁ and M₃ has channel length modulation?

R / ((1/g + 4R) * g * R / ((1/g || r) + 3R)

R / ((1/g) * R * R * g * 4g

R / ((1/g || r) + R) * g * R * R / ((1/gm || r))

R / ((1/g || r)) * g *R * R / ((1/g || r) + 2R)

8. The input impedance of the follower stage is ____________ than that of a CG stage.

equal

lesser

cannot be compared

greater

9. How can the duty cycle be changed for an astable multivibrator?

By adding another capacitor to the circuit

By adding diodes to the circuit

The duty cycle cannot be changed

By adding an inductor to the circuit

10. In the following C.S. stage, what is the gate voltage appearing across M₁?

V₁ * [(R₂ || R₃) / {R₁ + (R₂ ||R₃}]

V₁ * [(R₂ || R₃) / (R₁ || R₂ || R₃)]

V₁ * [(R₂ + R₃) / (R₁ + R₂ + R₃)]

V₁ * [(R₂ + R₃) / {R₁ + R₂) || R₃}]