InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
The system in the given figure, has |
| Answer» Since the plot is very near (-1 + j0) point, gain margin is poor. | |
| 102. |
The given figure shows a pole zero diagram. The transfer function G(1) is |
| Answer» Join j1 point with the zero and poles. Find magnitude and phase angles of all these lines. | |
| 103. |
For very low frequencies, / in the given figure equals |
| Answer» For low frequencies Xc is very high as compared to R. Hence . | |
| 104. |
In a minimum phase system |
| Answer» For stability poles must be in left half plane. Zeros in left half plane lead to minimum phase shift. | |
| 105. |
For the system of the given figure the transfer function is |
| Answer» Transfer function = . | |
| 106. |
In the given figure shows pole-zero plot. If steady state gain is 2 the transfer function G() is |
| Answer» The zero at - 1 gives the term (s + 1) in the numerator. The poles at (- 2 + j1) and (- 2 - j1) give (s2 + 4s + 5) term is the denominator. Gain is 2. | |
| 107. |
If a system is to follow arbitrary inputs accurately the bandwidth should be |
| Answer» Arbitrary inputs require large bandwidth. | |
| 108. |
For the system of the given figure, the damping ratio of closed loop poles is |
| Answer» The standard form of characteristic equation is . Therefore . | |
| 109. |
For the control system in the given figure, the value of K for critical damping is |
| Answer» since ζ = 1, ωn = 3.5 Hence 2 + 2k = 3.52 = 12.25 or K = 5.125 . | |
| 110. |
Bode magnitude plot is drawn between |
| Answer» Frequency is plotted on log scale and magnitude is taken in dB. | |
| 111. |
For the system in the given figure, |
| Answer» For inner loop we have transfer function = Then = . | |
| 112. |
In the given figure, if R = X, voltage gain is |
| Answer» If R = XC, V0 = 0.5 Vi Hence gain is -3 dB. | |
| 113. |
For the circuit in the given figure, V()/V() = |
| Answer» . | |
| 114. |
If error voltage is (), integral square error = |
| Answer» Error is squared and integrated. | |
| 115. |
A lag compensator is essentially a |
| Answer» See transfer function in the equation , β > 1 where t1 = R1C1, t2 = R2C2 and t > 1. | |
| 116. |
Stepper motors find applications in |
| Answer» Stepper motors are used in all these applications. | |
| 117. |
In the given figure the input frequency is such that |
| Answer» Voltage across capacitor lags by 90°. | |
| 118. |
The phase margin and damping ratio have no relation. |
| Answer» They are related. | |
| 119. |
For the transport lag G(ω) = , the magnitude is always equal to |
| Answer» Magnitude is 1. | |
| 120. |
The log magnitude curve for a constant gain K is a |
| Answer» The factor K in the numerator of G(jω) gives is straight line at 20 log10 K in Bode plot. | |
| 121. |
The compensator of the given figure is a |
| Answer» Obtain transfer function. | |
| 122. |
In the given figure, of potentiometer V = V (R/R) only when |
| Answer» If RL is not infinite, the voltage ratio of potentiometer depends on the value of RL. This is called loading effect. | |
| 123. |
A unity feedback system has open loop transfer function The closed loop transfer function is |
| Answer» . | |
| 124. |
Bellows converts |
| Answer» To measure pressure, it is convenient to convert pressure into displacement and then use a displacement transducer. | |
| 125. |
For type 2 system, the magnitude and phase angle of the term (ω) in the denominator, at ω = 0, are respectively |
| Answer» If ω = 0, has a magnitude of infinity and phase angle -180°. | |
| 126. |
In an integral controller |
| Answer» Output is proportional to integral of input or rate of change of output is proportional to input. | |
| 127. |
In Bode diagram (log magnitude plot) the factor in the transfer function gives a line having slope |
| Answer» For term the slope is -20 dB/decade or -6 dB/octave because - 20 log 2 = -6 dB. | |
| 128. |
In the given figure the input is () = A sin ω. The steady state output () = |
| Answer» The magnitudes A and G(jω) are multiplied and phase angles are added. | |
| 129. |
In the given figure = |
| Answer» The input x1 is multiplied by a, x2, by b and x3 by c. The sum total is multiplied by d and e. | |
| 130. |
First column elements of Routh's tabulation are 3, 5, , 2. It means that there |
| Answer» Since there are two sign changes in the first column, hence two roots in right half plane. | |
| 131. |
When a unit step voltage drives a lag network the output |
| Answer» At t = 0 the capacitor behaves as a short-circuit and output voltage is 0. At t = ∞ capacitor behaves as an open-circuit and V0 = Vi. | |
| 132. |
For the given figure C()/R() |
| Answer» . | |
| 133. |
For the circuit in the given figure, |
| Answer» . | |
| 134. |
A system has its two poles on the negative real axis and one pair of poles lies on ω axis. The system is |
| Answer» Poles on j x-axis lead to oscillations. | |
| 135. |
A negative feedback system has . The closed loop system is stable for |
| Answer» Find characteristic equation. | |
| 136. |
For the given figure, |
| Answer» For the inner loop, transfer function = Then . | |
| 137. |
A stepper motor is |
| Answer» When input pulses are applied, the motor moves in steps. | |
| 138. |
In a two phase ac servomotor rotor resistance is R and rotor reactance is X. The speed curve will be linear if |
| Answer» In a two phase servomotor ∠ < 1 so that torque speed curve is almost linear. | |
| 139. |
In the given figure, the input frequency is such that R = X. Then |
| Answer» R = XC, voltage drops across R and XC are equal and at 90° with respect by each other. V0 lags Vi by 45°. | |
| 140. |
From the noise point of view, bandwidth should |
| Answer» If noise is to be eliminated, bandwidth cannot be large. | |
| 141. |
For a first order system having transfer function , the unit impulse response is |
| Answer» | |
| 142. |
For the system in the given figure the characteristic equation is |
| Answer» Transfer function = . Hence characteristic equation is . | |
| 143. |
Mechanical impedance is the ratio of |
| Answer» In force voltage analogy force is analogous to voltage and velocity to current. Just as , force/velocity = mechanical impedance. | |
| 144. |
For the system in the given figure. The transfer function C()/R() is |
| Answer» Transfer function = (G1 + 1) G2 + 1 = G1 G2 + G2 + 1. | |
| 145. |
Whether a linear system is stable or unstable that it |
| Answer» Stability is a property of the system only. | |
| 146. |
For the system of the given figure the transfer function = |
| Answer» , E0(s) = [I(s)][Z2(s)] or . | |