Root Locus Diagram · Control Systems · GATE ECE
Marks 1
1
The root-locus plot of a closed-loop system with unity negative feedback and transfer function KG(s) in the forward path is shown in the figure. Note that K is varied from 0 to $$\infty$$.
Select the transfer function G(s) that results in the root-locus plot of the closed-loop system as shown in the figure.
GATE ECE 2022
2
The root locus plot for a system is given below. The open loop transfer function
corresponding to this plot is given by
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GATE ECE 2011
3
Which of the following points is NOT on the root locus of a system with the open
loop transfer function
$$$G\left(s\right)H\left(s\right)=\frac K{s(s+1)(s+3)}$$$
GATE ECE 2002
4
Given the $$G\left(s\right)H\left(s\right)=\frac K{s\left(s+1\right)\left(s+3\right)}$$, the point of intersection of the asymptotes
of the root loci with the real axis is
GATE ECE 2001
5
The root-locus diagram for a closed loop feedback system is shown in Figure. The system is overdamped.
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GATE ECE 2001
6
If the open loop transfer function is a ratio of a numerator polynomial of degree
'm' and a denominator polynomial of degree 'n', then the integer (n-m)
represents the number of
GATE ECE 1994
Marks 2
1
A linear time invariant (LTI) system with the transfer function
$$$G\left(s\right)=\frac{K\left(s^2+2s+2\right)}{s^2-3s+2}$$$
is connected in unity feedback configuration as shown in the figure.
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For the closed loop system shown, the root locus for 0 < K < $$\infty$$ intersects the imaginary axis for K = 1.5. The closed loop system is stable for
GATE ECE 2017 Set 1
2
The open-loop transfer function of a unity-feedback control system is
$$$G\left(s\right)=\frac K{s^2+5s+5}$$$
The value of K at the breakaway point of the feedback control system's root-locus plot is
_____________
GATE ECE 2016 Set 1
3
The forward-path transfer function and the feedback-path transfer function of a single loop negative
feedback control system are given as $$G\left(s\right)=\frac{K\left(s+2\right)}{s^2+2s+2}$$ and H(s) = 1 respectively.If the variable parameter K is real positive, then the location of the breakaway point on the
root locus diagram of the system is_____________.
GATE ECE 2016 Set 3
4
For the system shown in the figure, s = –2.75 lies on the root locus if K is_____.
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GATE ECE 2015 Set 3
5
The open-loop transfer function of a plant in a unity feedback configuration is given as $$G\left(s\right)=\frac{K\left(s+4\right)}{\left(s+8\right)\left(s^2-9\right)}$$.The value of the gain K(>0) for which -1 + j2 lies on the root locus
is __________________.
GATE ECE 2015 Set 1
6
The characteristic equation of a unity negative feedback system 1 + KG(s) = 0. The open loop
transfer function G(s) has one pole at 0 and two poles at -1. The root locus of the system for
varying K is shown in the figure.
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The constant damping ratio line, for $$\xi$$ = 0.5 , intersects the root locus at point A. The distance from the origin to point A is given as 0.5. The value of K at point A is ________ .
GATE ECE 2014 Set 4
7
In the root locus plot shown in the figure, the pole/zero marks and the arrows have been
removed. Which one of the following transfer functions has this root locus?
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GATE ECE 2014 Set 3
8
A unity feedback control system has an open-loop transfer function
$$$G\left(s\right)=\frac K{s\left(s^2+7s+12\right)}$$$
The gain K for which s = −1 + j1 will lie on the root locus
of this system is:
GATE ECE 2007
9
A unity feedback system is given as,$$$G\left(s\right)=\frac{K\left(1-s\right)}{s\left(s+3\right)}$$$ indicate the correct root locus diagram.
GATE ECE 2005
10
The root locus of the system $$$G\left(s\right)H\left(s\right)=\frac K{s\left(s+2\right)\left(s+3\right)}$$$ has the break-away point
located at
GATE ECE 2003
11
Consider the points s1 = −3 + j4 and s2 = −3 − j2 in the s-plane. Then, for a system with the open loop transfer function
$$$G\left(s\right)H\left(s\right)=\frac K{\left(s+1\right)^4}$$$
GATE ECE 1999
12
Given a unity feedback system with open loop transfer function,
$$$G\left(s\right)=\frac K{s\left(s+1\right)\left(s+2\right)}$$$
The root locus plot of the system is of the form.
GATE ECE 1992
13
The characteristic equation of a feedback control system is given by
s3 +5s2 +(K + 6)s + K =0
Where K > 0 is a scalar variable parameter. In the root loci diagram of the system the asymptotes of the root locus for large values of K meet at a point in the s-plane whose coordinates are
s3 +5s2 +(K + 6)s + K =0
Where K > 0 is a scalar variable parameter. In the root loci diagram of the system the asymptotes of the root locus for large values of K meet at a point in the s-plane whose coordinates are
GATE ECE 1991
14
Consider a closed-loop system shown in fig. (a) below. The root locus for it is shown in fig. (b). The closed-loop transfer function for the system is
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GATE ECE 1988