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A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency. This is __________ criterion.
A
Bode stability
B
Nyquist
C
Routh stability
D
None of these
Correct Answer:
Bode stability
According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is
A
0°
B
45°
C
90°
D
180°
Assertion (A): The closed loop stability can be determined from the poles of an open loop system and the polar plot of the frequency response. Reason (R): Unstable system has right half poles.
A
Both A and R are true and R is correct explanation of A
B
Both A and R are true and R is not correct Explanation of A
C
A is True and R is false
D
A is False and R is true
A certain inverting amplifier has a closed-loop voltage gain of 25. The OP-amp has an open-loop voltage gain of 100,000. If an OP-amp with an open-loop voltage gain of 200,000 is substituted in the arrangement, the closed-loop gain
A
doubles
B
drops to 12.5
C
remains at 25
D
increases slightly
Which of the following is/are the advantages of using a control chart for inspection? (i) A control chart indicates whether the process is in control or out of control. (ii) A control chart determines process variability. (iii) A control chart ensures product quality. (iv) Scrap or percentage reduction can be reduced by taking the necessary actions in time against the warnings indicated by control charts. (v) Control charts build up the reputation of the organization through customer’s satisfaction. (vi) The control chart can detect the unusual variations taking place in a process.
A
i, ii, iii only
B
i, iv, v only
C
i, ii, iii, iv, v and vi
D
iv, v and vi
The open loop control transfer function of a unity feedback system is given by : G(s) =K/(s+2)(s+4)(s^2+6s+25) Which is the value of K which causes sustained oscillations in the closed loop system?
A
590
B
790
C
990
D
1190
The open-loop transfer function of a unity feedback system is K/(s^2 (s+5))The system is unstable for
A
K>5
B
K<5
C
K>0
D
All of the mentioned
For a stable system having two or more gain crossover frequencies the phase margin is measured at the highest crossover frequency.
A
True
B
False
Consider the following statements: Nichol’s chart gives information about. i. Closed loop frequency response. ii. The value of the peak magnitude of the closed loop frequency response Mp. iii. The frequency at which Mp occurs. Which of the above statements are correct?
A
2 and 3
B
1 and 2
C
1 and 3
D
1,2 and 3
The open loop transfer functions with unity feedback are given below for different systems. Among these systems the unstable system is
A
G(s) =2/s+2
B
G(s) =2/s(s+2)
C
G(s) =2/(s+2)s^2
D
G(s) =2(s+1)/s(s+2)
Consider a conducting loop of radius a and total loop resistance R placed in a region with a magnetic field B thereby enclosing a flux $${\phi _0}$$ . The loop is connected to an electronic circuit as shown, the capacitor being initially uncharged.
If the loop is pulled out of the region of the magnetic field at a constant speed u, the final output voltage V
out
is independent of
A
$${\phi _0}$$
B
u
C
R
D
C
