The unit step response of a 2 pole system is shown in the applet below. The poles are Complex Conjugate and are located at -a - jb and -a + jb. The applet shows 2 responses for different a for comparison.

The open and closed loop transfer function for the system is

G(s) = K/((s + a + jb)(s + a - jb)), C(s)/R(s) = K/((s + a + jb)(s + a - jb) + K))

The denominator of the closed loop transfer function can be written as s

The poles of the closed loop transfer function with a is shown in the applet.

Gif image below shows how applet should appear.

COPYRIGHT © 2006 Cuthbert Nyack.