# Test: Control System - 1

## 15 Questions MCQ Test GATE ECE (Electronics) 2023 Mock Test Series | Test: Control System - 1

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Attempt Test: Control System - 1 | 15 questions in 45 minutes | Mock test for Electronics and Communication Engineering (ECE) preparation | Free important questions MCQ to study GATE ECE (Electronics) 2023 Mock Test Series for Electronics and Communication Engineering (ECE) Exam | Download free PDF with solutions
QUESTION: 1

### Determine C/R for the system given in figure below. Then put G3 = G1 G2 H2. Now the new transfer function will be: Solution:    QUESTION: 2

### The signal-flow graph shown in figure below has: Solution:

Forward paths are: Loops are: *Answer can only contain numeric values
QUESTION: 3

### The unit impulse response of a system is h(t) = e-2t, t 0. For this system, the steady-state value of the output for unit step input is equal to

Solution: and   QUESTION: 4

A control system has input r(t) and output c(t). If the input is first passed through a block

whose transfer function is a-2s and then applied to the system, the modified output will be

Solution:  QUESTION: 5

The open-loop transfer function of a feedback control system is given by G(s) Find the range of the values of T for stability.

Solution:

The characteristic equation of the system is   s2 + s(2 — T) + 1 = 0

Routh's array becomes: The system will be stable if QUESTION: 6

If the open-loop transfer function of a feedback system is given by

G(s) H(s) = , then the controid of the asymptotes will be

Solution:

Poles = 0, —2, —1 + 2j, —1 —2j

Total number of pole, P = 4

Total number of zero, Z = 0
∴           P — Z = 4

∴ QUESTION: 7

For the block diagram shown in figure below, the limiting value of k for stability of the inner loop is found to be X < k < Y. The overall system will be stable if and only if Solution:

For inner loop:  let

For outer loop:   QUESTION: 8

The closed loop transfer function of a control system has the following poles and zeros

Poles                                                       Zeros

P1 =    0.5                                                          Z1 = –7

P2 = –1.0                                                          Z2 = 9

P3 = –5

P4 = —10

The closed loop response can be closely approximated by considering which of the following?

Solution:

Because of concept of dominant pole. Here P1 and P2 are dominant pole and P3 and P4 are

insignificant poles.

QUESTION: 9

Match List-I (Type of compensator) with List-II (Polar plot) and select the correct answer using the code given below the lists:

List-I 2. Phase lag 3. Lead-lag A B C

(a)123

(b) 132

(c) 213

(d) 231

Solution:
QUESTION: 10

For the given network, the maximum phase lead 4m of Vo with respect to V1 is Solution:  QUESTION: 11

In the Bode-plot of a unity feedback control system, the value of phase of G(j@) at the gain

cross-over frequency is —125°. The phase margin of the system is

Solution:

φ at ωg C = —125°

Phase-margin (PM) = 180°+ φ

= 180°— 125°

= 55°

QUESTION: 12

The Nyquist plot for the function is  The condition for stability is given by

Solution:
QUESTION: 13

The open-loop transfer function of unity feedback system is G(s) = . Thes (s + 2) (s + 10)range of k for which closed-loop system is stable.

Solution:

It is type-1 and order —3 system so the Nyquist plot is    For stability: QUESTION: 14

The Bode plot for minimum phase transfer function is:

Solution:

(a)

1. In option (a) Bode plot represents - Minimum phase transfer function
2. In option (b) Bode plot represents - Non-minimum phase transfer function
3. In option (c) Bode plot represents - All pass transfer function
QUESTION: 15

For the system shown below the state-space equation is X = A x + B u. The matrix A is Solution:

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