Two-Port Network MCQ

1. The Z-matrix of a 2-port network is given by

$Z=\begin{bmatrix} 0.9 & 0.2\\ 0.2 & 0.6 \end{bmatrix}$

The element Y₂₂ of the corresponding Y matrix of the same network is given by

1. 1.2
2. 0.4
3. -0.4
4. 1.8

2. A passive two-port network is in a steady state. Compared to its input, the steady-state output can never offer

1. higher voltage
2. lower impedance
3. greater power
4. better regulation

3. If a two-port network is reciprocal, then we have, with the usual notation, the following relationship

1. h₁₂ = h₂₁
2. h₁₂ = -h₂₁
3. h₁₁ = h₂₂
4. h₁₁h₂₂ – h₁₂h₂₁ = 1

4. A two-port device is defined by the following pair of equations:

i₁ = 2v₁ + v₂ and i₂ = v₁ + v₂

Its impedance parameters $\begin{bmatrix} z_{11} & z_{12}\\ z_{21} & z_{22} \end{bmatrix}$ are given by

1. $\begin{bmatrix} 2 & 1\\ 1 & 1 \end{bmatrix}$
2. $\begin{bmatrix} 1 & -1\\ -1 & 2 \end{bmatrix}$
3. $\begin{bmatrix} 1 & 1\\ 1 & 2 \end{bmatrix}$
4. $\begin{bmatrix} 2 & -1\\ -1 & 1 \end{bmatrix}$

5. In a linear two-port network, when 10 V is applied to port 1, a current of 4 A flows through port 2 when it is short-circuited. When 5 V is applied to port 1, a current of 1.25 A flows through a 1 Ω resistance connected across port 2. When 3 V is applied to port 1, the current (in Ampere) through a 2 Ω resistance connected across port 2 is

1. 0.545
2. 0.490
3. 0.360
4. 0.708

6. Consider the following standard symbols for two-port parameters:

1. h₁₂ and h₂₁ are dimensionless
2. h₁₁ and B have dimensions of ohms
3. BC is dimensionless
4. C is dimensionless

Which of the above are correct?

1. i, ii and iii only
2. i, ii and iv only
3. iii and iv only
4. i, ii, iii and iv

7. A 2-port network is represented by the following equations

V₁ = 60I₁ + 20I₂

V₂ = 20I₁ + 40I₂

The ABCD parameters of the above network would be

1. $\begin{bmatrix} 2 & \frac{1}{20}\\ 3 & 100 \end{bmatrix}$
2. $\begin{bmatrix} 100 & 3\\ 2 & \frac{1}{20} \end{bmatrix}$
3. $\begin{bmatrix} 100 & 20\\ 6 & 3 \end{bmatrix}$
4. $\begin{bmatrix} 3 & 100\\ \frac{1}{20} & 2 \end{bmatrix}$

8. The condition for reciprocity for a two-port transmission network is expressed by

1. $\begin{vmatrix} A & B\\ C & D \end{vmatrix}=0$
2. $\begin{vmatrix} A & D\\B & C \end{vmatrix}=1$
3. $\begin{vmatrix} A & C\\ B & D \end{vmatrix}=0$
4. $\begin{vmatrix} A & B\\ C & D \end{vmatrix}=1$

9. A 2-port network is defined by the relation,

$V_1=\frac{3}{4}I_1-\frac{1}{4}I_2\; , V_2=-\frac{1}{2}I_1+\frac{1}{2}I_2\;$

Then y₁₂ is

1. 0.5 mho
2. -0.5 mho
3. 1 mho
4. -1 mho

10. A two-port network is described by the following equations

V₁ = 50I₁ + 20I₂

V₂ = 30I₁ + 10I₂

Then, which one of the following is not correct?

1. Z₁₂ = 20 Ω
2. Y₁₂ = 0.2 mho
3. h₁₂ = 2
4. A = 25

11. A two-port network is defined by the relation:

I₁ = 5V₁ + 3V₂

I₂ = 2V₁ – 7V₂

The value of z₁₂ is

1. 3 Ω
2. -3 Ω
3. 3/41 Ω
4. 2/31 Ω

12. A, B, C and D represent the transmission parameters of a two-port network. When is the network reciprocal?

1. AB – CD = 1
2. AD – BC = 1
3. AB – CD = 0
4. AD – BC = 0

13. The h parameters h₁₁ and h₂₂ are related to z and y parameters as

1. h₁₁ = z₁₁ and h₂₂ = 1/z₂₂
2. h₁₁ = z₁₁ and h₂₂ = y₂₂
3. h₁₁ = 1/y₁₁ and h₂₂ = 1/z₂₂
4. h₁₁ = 1/y₁₁ and h₂₂ = y₂₂

14. For a two-port symmetrical bilateral network, if transmission A = 2 and B = 1 ohm, then the value of parameter C is equal to

1. 3 ohms
2. 6 ohms
3. 9 ohms
4. 12 ohms

15. The two-port parameter h₂₁ is called

1. open-circuit output admittance
2. short-circuit input impedance
3. open-circuit reverse voltage gain
4. short-circuit forward current gain

16. In a two-port network how hybrid parameter is expressed

1. V₁, I₂
2. Y₁, I₁
3. I₁, I₂
4. V₁, V₂

17. When analysing two port network in cascade, which of the following is more convenient to use?

1. z-parameters
2. h-parameters
3. T-parameters
4. y-parameters

18. A two port network is reciprocal if

1. Y₁₁ = Y₂₂
2. Y₁₂ = Y₂₁
3. Y₁₂ = -Y₂₁
4. Y₂₂ = Y₂₁

19. For a two port reciprocal network, the three transmission parameters are given by A = 3/5, B = 7/5, C = 4/5, what is the value of D?

1. 1
2. 3/5
3. 53/15
4. 1/2

20. Which of the following expression shows correct function for ‘Y’ parameter in a two port network?

1. (V₁, V₂) = f(I₁, I₂)
2. (I₁, I₂) = f(V₁, V₂)
3. (V₁, I₁) = f(V₂, -I₂)
4. (V₁, I₂) = f(I₁, V₂)

21. Two terminals constitute a “Port”, if they satisfy port condition. The port condition indicates

1. current entering one terminal is equal to the current leaving the other terminal
2. current entering one terminal and leaving the other terminal is different
3. no current must enter and leave a port
4. all the above

22. A network is said to be reciprocal if

1. Z₁₂ = Z₂₁
2. Y₁₂ = Y₂₁
3. AD – BC = 1
4. all of these

23. Two port networks are connected in cascade. The combination is to represent as a single two-port networks. The parameters of the network are obtained by multiplying the individual

1. z-parameter matrix
2. h-parameter matrix
3. y-parameter matrix
4. ABCD parameter matrix

24. Which of the following conditions holds good for a 2-port network to be reciprocal?

1. Z₁₁ = Z₂₂
2. h₁₂ = h₂₁
3. Y₁₂ = Y₂₁
4. BC – AD = -1

25. In terms of ABCD parameters, a two port network is symmetrical if and only if

1. A = B
2. B = C
3. C = D
4. D = A

26. A passive 2-port network is in a steady-state. Compared to its input, the steady state output can never offer

1. higher voltage
2. lower impedance
3. greater power
4. better regulation