Quize Part 2

Which of the following, is an advantage of using a Star-Delta motor starter, compared to a Direct On Line starter?

• Access is needed to both ends of the motor windings

• More contactors are used.

• Lower starting current

• Lower starting torque

What sort of fuse would you select for an installation that required high current interrupting ability, and an allowance for instantaneous over currents?

• A thermal circuit breaker

• A nail

• A magnetic circuit breaker

• HRC fuse

Which of the following is not the feature of a modern control system?

• Correct power level

• No oscillation

• 
  Quick response

• Accuracy

A control system working under unknown random actions is called ____________

• Adaptive control system

• Stochastic control system

• Computer control system

• Digital data system

Consider the following statements with respect to the feedback of the control systems.
i. Feedback can improve stability or be harmful to stability if it is not properly applied.
ii. Feedback can always improve stability
iii. In many situations the feedback can reduce the effect of noise and disturbance on system performance.
iv. In general the sensitivity of the system gain of a feedback system of a parameter variation depends on where the parameter is located.

• i, ii, iii and iv only

• i, ii and iii only

• i, iii and iv only

• i, ii and iv only

The characteristic equation of a control system is given by s(s+4)(s²+2s+s) + k(s+1) = 0. What are the angles of the asymptotes for the root loci?

• 0°, 180°, 300°

• 0°, 120°, 240°

• 60°, 180°, 300°

• 120°, 180°, 240°

A basic S-R flip-flop can be constructed by cross-coupling of which basic logic gates?

• AND or OR gates

• XOR or XNOR gates

• NOR or NAND gates

• AND or NOR gates

Which of the circuits in figure (a to d) is the sum-of-products implementation of figure?

• 
• 
• 
• 

Which of the following logic expressions represents the logic diagram shown?

• X=AB’+A’B

• X=(AB)’+AB

• X=(AB)’+A’B’

• X=A’B’+AB

For a two-input XNOR gate, with the input waveforms as shown below, which output waveform is correct?

• d

• a

• c

• b