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Electronics and Communication Engineering - Automatic Control Systems

Exercise : Automatic Control Systems - Section 2
11.
For the system in the given figure, the transfer function C(s)/R(s) is
G1 + G2 + G3
G1 G2 + G3
G1 G2 G3
(G1 + G2) G3
Answer: Option
Explanation:

G1 and G2 are cascaded.

12.
For the system in the given figure, the characteristic equation is
s2 + s(3 + 6a) + 6 = 0
s2 + s(3 + 12a) + 12 = 0
s2 + 3s = 0
s2 + 6s = 0
Answer: Option
Explanation:

Transfer function to inner loop = .

Then .

The characteristic equation is s2 + 3s + 6as + 6 = 0.

13.
In control systems the magnitude of error voltage
is very small
is very large
neither small nor large
may be any value from 0 to 50 V
Answer: Option
Explanation:

The error voltage is always very small. A high value of error voltage may cause instability.

14.
The slope of log-magnitude asymptote changes by - 40 dB/ decade at a frequency ω1. This means that
a double pole is present
a pair of complex conjugate poles is present
either a double pole or a pair of complex conjugate poles is present
a pole or zero at origin is present
Answer: Option
Explanation:

A double pole or pair of complex poles result in - 40 dB/decade slope in log magnitude graph.

15.
In the given figure the transfer function
Answer: Option
Explanation:

Use signal flow graph.

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