**2003**

1. A PD controller is used to compensate a system. Compared to the uncompensated system, the compensated system has

a) a higher type number

b) reduced damping

c) higher noise amplification

d) larger transient overshoot

**Solution :**

**https://www.youtube.com/watch?v=flVQh4IItX4**

**2005**

2. Which one of the following polar diagrams corresponds to a lag network?

**Solution :**https://www.youtube.com/watch?v=essJrzYsfPg

**2006**

3. The transfer function of a phase lead compensator is given by G

_{c}(s) = (1 + 3Ts)/(1 + Ts) where T ≥ 0. The maximum phase shift provided by such a compensator is

a) π/2

b) π/3

c) π/4

d) π/6

**Solution :**https://www.youtube.com/watch?v=B6_LDoAZ3-I

**2007**

4. A control system with a PD controller is shown in the figure.

If the velocity error constant K

_{v}= 1000 and the damping ratio ξ = 0.5, then the values of K

_{p}and K

_{D}are

a) K

_{p}= 100, K

_{D}= 0.09

b) K

_{p}= 100, K

_{D}= 0.9

c) K

_{p}= 10, K

_{D}= 0.09

d) K

_{p}= 10, K

_{D}= 0.9

**Solution :**https://www.youtube.com/watch?v=vxHx4zTs5vg

5. The open loop transfer function of a plant is given as G(s) = 1

**/**(s

^{2}– 1). If the plant is operated in a unity feedback configuration, then the lead compensator that can stabilize this control system is

**Solution :**https://www.youtube.com/watch?v=HJ09FtxcO-I

**2008**

6. Group – I gives two possible choices for the impedance Z in the diagram. The circuit elements in Z satisfy the condition R

_{2}C

_{2}>R

_{1}C

_{1}. The transfer function V

_{o}/V

_{1}represents a kind of controller. Match the impedance's in Group – I with the types of controllers in Group – II.

a) Q – 1, R – 2

b) Q – 1, R – 3

c) Q – 2, R – 3

d) Q – 3, R – 2

**Solution :**https://www.youtube.com/watch?v=Q3O1G2CU5Xw

**2009**

7. The magnitude plot of a rational transfer function G(s) with real coefficients is shown below. Which of the following compensator has such a magnitude plot?

a) Lead compensator

b) Lag compensator

c) PID compensator

d) Lead – Lag compensator

**Solution :**https://www.youtube.com/watch?v=JVBUSrYEb7Q

8. If the transfer function of the following circuit is V

_{o}(s)/V

_{i}(s) = 1/(2+sCR), then the value of the load resistor R

_{L}is

a) R/4

b) R/2

c) R

d) 2R

**Solution :**https://www.youtube.com/watch?v=0bJX_BCy6bc

**2010**

9. A unity negative feedback closed loop system has a plant with the transfer function G(s) = 1/(s

^{2}+ 2s + 2) and a controller G

_{c}(s) in the feed forward path. For a unit step input, the tranfer function of the controller that gives minimum steady state error is

**Solution :**https://www.youtube.com/watch?v=zdwjtNkiBxg

**2012**

**Statement for Linked Answer Questions : 10 and 11**

The transfer function of a compensator is given as G

_{c}(s)= (s+a)/(s+b).

10. G

_{c}(s) is a lead compensator if

a) a = 1, b =2

b) a = 3, b =2

c) a = –3, b = –1

d) a = 3, b =1

11. The phase of the above lead compensator is maximum at

a) √2 rad/sec

b) √3 rad/sec

c) √6 rad/sec

d) 1/√3 rad/sec

**Solution (6 & 7) :**https://www.youtube.com/watch?v=CSWEFDPoSsA

**2015**

12. A lead compensator network includes a parallel combination fo R and C in the feed-forward path. If the transfer function of the compensator is GC(s) = (s+2)/(s+4) , the value of RC is ___________

**Solution :**https://www.youtube.com/watch?v=DeKH-DPUdMo

13. The transfer function of a first order controller is given as Gc(s) = K(s+a) / (s+b), where K, a and b are positive real numbers. The condition for this controller to act as a phase lead compensator is

a) a < b

b) a > b

c) K < ab

d) K > ab

**Solution :**https://www.youtube.com/watch?v=uKr3VkkMkow