Question

A ramp input applied to a unity feedback system results in 5% steady state error. The type number and zero frequency gain of the system are respectively

(a) 1 and 20

(b) 0 and 20

(c) 0 and 1/20

(d) 1 and 1/20

This question was addressed to me in a job interview.

This is a very interesting question from Steady-state Errors and Error Constants topic in chapter Time Response Analysis, Design Specifications and Performance Indices of Control Systems

Answer 1

The correct option is (a) 1 and 20

Easy explanation: Steady state error is the error calculated between the final output and desired output and for the good control system the error must be less and this steady state error is inversely proportional to gain.