“A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency.” This is _______________ criterion?

Related Mcqs:

1. According to Bode stability criterion, 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°

2. The frequency response of a dynamic element shows a constant magnitude ratio at all frequencies. The element exhibits a negative phase shift at all frequencies. The absolute value of the phase shift increases linearly with frequency. The element has the transfer function ?

   A. e-ηS
   B. (T1S + 1)/(T2S + 1)
   C. (T1S/(T2S + 1)
   D. (T1S + 1)/(T2S

3. A first order system with unity gain and time constant η is subjected to a sinusoidal input of frequency w = 1/η. The amplitude ratio for this system is______________?

   A. 1
   B. 0.5
   C. 1/√2
   D. 0.25

4. The frequency at which maximum amplitude ratio is attained is called the ______________ frequency?

   A. Corner
   B. Resonant
   C. Cross-over
   D. Natural

5. In a feed-back control system G and H denote open loop and close loop transfer functions respectively. The output-input relationship is_____________?

   A. G/(1 + H)
   B. H/(1 + G)
   C. G/H
   D. H/G

6. The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function K (s + 1)/[2 (2s + 1) (3s + 1)] will have a definite number of loci for variation of K from 0 to ∞. The number of loci is_______________?

   A. 1
   B. 2
   C. 3
   D. 4

7. What is the ratio of output amplitude to input amplitude for a sinusoidal forcing function in a first order system ?

   A. 1
   B. > 1
   C. < 1
   D. None of these

8. The amplitude ratio for the sinusoidal response of __________ is < 1?

   A. Transportation lag
   B. First order system
   C. Second order system
   D. None of these

9. The amplitude ratio for the sinusoidal response of a _____________ is 1?

   A. First order system
   B. Second order system
   C. Transportation lag
   D. None of these

10. In a closed loop system, the process to be controlled is an integrating process with transfer function 1/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit__________________?

    A. Overdamped response
    B. Underdamped response
    C. Undamped response
    D. Unstable response