Electronics and Communication Engineering - Automatic Control Systems

46.
The polar plot of
does not cross real axis
crosses real axis
crosses real axis at ω = 0.7 rad/sec
crosses real axis at ω = 1.4 rad/sec
Answer: Option
Explanation:

It does not become real at any frequency.


47.
In a second order undamped system, the poles are on
positive real axis
imaginary axis
negative real axis
either (a) or (c)
Answer: Option
Explanation:

If poles are on imaginary axis the response is undamped and oscillatory.


48.
For the system of the given figure, the undamped natural frequency of closed loop poles is
2 rad/sec
1 rad/sec
0.5 rad/sec
0.25 rad/sec
Answer: Option
Explanation:

.


49.
An open loop system has a forward path transfer function (42.25)/s(s + 6.5). The unit step response of the system starting from rest will have its maximum value at a time equal to
0 sec
0.56 sec
5.6 sec
infinity
Answer: Option
Explanation:

Unit step response is Taking inverse transform, the time domain response is - 1 + 6.5t + e-6-5t. It reaches maximum value at t = infinity.


50.
In the given figure
Answer: Option
Explanation:

Use block diagram algebra.