M.Sc.(Electronics) (Semester (CBCS) Examination, 2017
CONTROL THEORY
wateriI
Day Date: Wednesday, 19-04-2017 Max. Marks: 70
Time: 10.30 AM to 01.00 PM
N.B. Answer Five Questions.
Question 1 and 2 are compulsory.
Figures to the right indicate full marks
Attempt any Three from Q.3 to Q.7
Q.1 Choose correct answer. 08
If is open loop transfer function, then closed loop transfer
function is given by


2 The transfer function of the circuit containing R and C is given
by
1+Ts 1/Tsc
3 The time that the system output takes to reach 50% of its final
value is known time.
Rise time Settling time Peak time Delay time
4 In case of second order system if then poles are
Real and equal Imaginary and equal
Imaginary On positive real axis
5 If positional error constant is Kp then steady state error for
step input is given by ess
Kp 1+Kp A/Kp
6 If poles of the system are 4j then system is
Stable Unstable Quasi stable None of these
7 Frequency response is the response
Magnitude against log of frequency
Log of magnitude against frequency
Log of magnitude against log of frequency
Log of magnitude and phase against frequency
8 According to Angle condition the phase of the function
is given by
(2q+1)180 (2q)180
90 180
Page 2 of 3
State weather true or false: 06
Signal flow graph is applicable only to linear time invariant
system.
The standard test signal of the type ramp results into
positional error constant.
The transfer function is (1=s)).System is said to be
type 0system
If damping factor then the roots are imaginary and
complex conjugate.
According to Hurwitz`s criterion, for stable system all Hurwitz
determinant should be positive..
Nyquist polar plots are not suitable to express the stability of
the system.
Q.2 Attempt any two: 10
With suitable examples describe closed loop control system.
Discuss in detail the standard test signals.
What is frequency response of a system?
Give in detail classification of the controllers. 04
Q.3 What do you mean by feedback and feed forward control system?
Discuss with help of suitable block diagram.
08
Write a note on Poles and Zeros of the Transfer function of the
system.
06
Q.4 Define the terms transient response and steady state response. 08
Derive expression for stead state error for step, ramp and
parabolic inputs.
06
Q.5 Describe s-plane with respect to stability. How nature of the pole
is related to the stability of the system?
08
What do you mean by Routh-Hurwitz Criteria for stability? 06
Q.6 What is need of block diagram reduction? Explain in detail the rules 08
for block diagram reduction.
R
G C
Using standard rules reduce following block diagram. 06
Q.7 What is characteristic equation of second order transfer function? 08
G1 G2
G3
H1
H2


Page 3 of 3
Explain effect of damping factor on the performance of the
second order system.
What is concept of composite control mode? Discuss PI mode in
detail.