155. Basically a controller is

A. an amplifier

B. a clipper

C. a comparator

D. a summer

156. In a control system, when derivative action is included in a proportional controller, the proportional band

A. decreases

B. increases

C. remains unaltered

D. depends on derivative time constant

157. Dynamic equations are a set of equations formed on rutting together

A. input equations and output equations

B. state equations and input equations

C. output equations and state equations

D. input, output and state equations

158. For changing the time constant and providing sufficient damping in the control system, the factor responsible is

A. input signal

B. first derivative of the input signal

C. second derivative of the input signal

D. all of these

159. The first derivative control can be used to

A. decrease damping

B. decrease velocity lag error

C. decrease setting time

D. both B and C above

160. The peak overshoot in a control system is a function of

A. natural frequency of oscillation con alone damped frequency of oscillation cod alone

B. damping ratio only

C. none of these

D.

161. Presence of nonlinearities in a control system tends to introduce

A. transient error

B. instability

C. steady state error

D. all of these

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