摘要：The paper presents the computing of control circuits in the frequency domain, starting from the mathematical model of the frequency response H(j) obtained from the transfer function H(s) where the operational variable keeps just the image part. For PT1 and PT2 elements, using Scilab, the geometrical place is illustrated and the frequency diagrams are determinate for different duping constants (PT2). The logarithmic frequency diagrams (Bode), determine the amplitude and phase reserve for a control circuits with three PT1 elements.
