# Observer Systems

Observer Systems

1. A control system in which the control action is somehow dependent on the output is known as

a) Closed loop system
b) Semi closed loop system
c) Open system
d) Non feedback control system

Explanation: Closed system is a control system in which the feedback is present that can be positive or negative and in which the control action is somewhat dependent on the output.

2. In closed loop control system, with positive value of feedback gain the overall gain of the system will

a) Decrease
b) Increase
c) Be unaffected
d) Exponentially increase

Explanation: Closed loop control system, can be both positive and negative and with positive value of feedback gain where the overall gain of the system will increase and also the oscillations.

3. Which of the following is an open loop control system?

a) Field controlled D.C. motor
b) Ward Leonard control
d) Stroboscope

Explanation: Open loop control systems are the systems which have no feedback and cannot be used to obtain the desired response and field controlled system is an open loop control system.

4. Which of the following statements is not necessarily correct for open control system?

a) Input command is the sole factor responsible for providing the control action
b) Presence of non-linearities causes malfunctioning
c) Less expensive
d) Generally free from problems of non-linearities

Explanation: Open loop control system are the systems which have no feedback and cannot be used to obtain the desired response and non-linearities does not cause malfunctioning.

5. In open loop system

a) The control action depends on the size of the system
b) The control action depends on system variables
c) The control action depends on the input signal
d) The control action is independent of the output

Explanation: In open loop system the output cannot be used to obtain the desired response and the control action is independent of the output.

6. ___________has tendency to oscillate.

a) Open loop system
b) Closed loop system
c) Open and closed loop systems have tendency to oscillate
d) No Systems have tendency to oscillate

Explanation: Open loop control systems are the systems where the output cannot be the desired output and no feedback is used and gain of the system is very high due to this damping is very less and hence system has tendency to oscillate.

7. A good control system has all the following features except

a) Good stability
b) Slow response
c) Good accuracy
d) Sufficient power handling capacity

Explanation: A good control system is mainly negative feedback closed loop control system where the gain of system is not very high and damping is present and no oscillations are present and has fast output response.

8. A car is running at a constant speed of 50 km/h, which of the following is the feedback element for the driver?

a) Clutch
b) Eyes
c) Needle of the speedometer
d) Steering wheel

Explanation: For car as control system steering wheel is the feedback element for the driver as for driver to maintain constant speed or desired speed steering wheel is the important element and error detector.

9. The initial response when the output is not equal to input is called

a) Transient response
b) Error response
c) Dynamic response
d) All of the mentioned

Explanation: Transient response in the response at any time instant other than final response and this response is at any instant which is mainly dependent on the maximum peak overshoot and settling time.

10. A control system working under unknown random actions is called

a) Computer control system
b) Digital data system
c) Stochastic control system