LCS (B-TECH Electronics and Communication Engineering 4th)

Unit I Introductory Concepts:

 Plant, Systems, Servomechanism, regulating systems, disturbances, Open loop

control system, closed loop control systems, linear and non-linear systems, time variant and invariant, continuous

and sampled-data control systems, Block diagrams, some illustrative examples.

Unit II Modeling:

 Formulation of equation of linear electrical, mechanical, thermal, pneumatic and

hydraulic system, electrical, mechanical analogies. Transfer function, Block diagram representation, signal flow

graphs and associated algebra, characteristics equation.

Unit III Time Domain Analysis:

 Typical test - input signals, Transient response of the first and second

order systems. Time domain specifications, Dominant closed loop poles of higher order systems. Steady

state error and coefficients, pole-zero location and stability, Routh-Hurwitz Criterion.

Unit IV Root Locus Technique:

 The extreme points of the root loci for positive gain. Asymptotes to the

loci, Breakaway points, intersection with imaginary axis, location of roots with given gain and sketch of the

root locus plot.

Unit V Frequency Domain Analysis:

 Closed loop frequency response, Bode plots, stability and loop

transfer function. Frequency response specifications, Relative stability, Relation between time and frequency

response for second order systems. Log. Magnitude versus Phase angle plot, Nyquist criterion for stability. Unit

VI Compensation:

 Necessity of compensation, series and parallel compensation, compensating networks,

applications of lag and lead-compensation.

Unit VII Control Components: 

Error detectors - potentiometers and synchros, servo motors, a.c. and d.c.

techno generators, Magnetic amplifiers.