This web page illustrates the physical meaning of poles of transfer functions.
Transfer functions can be expressed as the ratio of two polynomials
H(s) = b(s)/a(s)
The poles p_i are solutions of the characteristic equation
a(s)=0
They are either real, or occur in complex conjugate pairs, and determine the basic waveform types that occur in currents and voltages in linear circuits. The illustrations below show the waveforms associated with locations in the complex frequency plane.
Last updated: February 25, 1999 / Matt James