Exam Questions Papers - Engineering

Q1:

A control system is as shown in given figure The maximum value of gain K for which the system is stable is

A more than 5

B equal to 5

C less than 1

D less than 5

ANS:D - less than 5

Characteristic Equation is 1 + GH = 0 1 + or s3 + 3s2 + 2s + (1 + K) = 0 Hurwitz criterion can be applied s3 1 2 and (1 + K) both should be + ve s2 3 1 + K s1 0 K should be more than - 1 and less than 5 s0 1 + K.