which component in multisim generates a bode plot

I used one microvolt peak for V2 and fed that to the top of R3 via one teraohm. To be sure, the circuit disruptive effect of V2 and R4 on the oscillator was negligible, but by including those two parts in the simulation, the Bode Plotter came to life and gave me a usable result. Maybe I could have put my one microvolt signal in series with R3 or something like that but I had what I needed so I didn’t look any further into it. To be sure, the Bode plot of the passive components alone and the Bode plot of those components in the oscillator differ slightly, but I chose to ascribe that difference to a slight loading effect, perhaps by the 2N4392 gate.

This article was originally published on EDN. John Dunn is an electronics consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York University (MSEE).Most of the interesting functions of AC circuits –complex impedance, voltage transfer function, and current transfer ratio– depend on frequency. The dependence of a complex quantity upon frequency can be represented on a complex plane (Nyquist diagram) or on real planes as separate plots of the absolute value (amplitude plot) and the phase (phase plot).īode plots use a linear vertical scale for the amplitude plot, but since dB units are used, the effect is that the vertical scale is plotted according to the logarithm of the amplitude. The amplitude A is presented as 20log10(A). The horizontal scale for frequency is logarithmic. Today, few engineers draw Bode plots by hand, relying instead on computers. TINA has very advanced facilities for Bode plots. Nevertheless, understanding the rules for drawing Bode plots will enhance your mastery of circuits. In the paragraphs that follow, we will present these rules and compare sketched straight-line approximation curves with TINA’s exact curves. The function to be sketched is generally a fraction or a ratio with a numerator polynomial and a denominator polynomial. The first step is to find the roots of the polynomials. The roots of the numerator are the zeros of the function while the roots of the denominator are the poles. Idealized Bode plots are simplified plots made up of straight-line segments. The end points of these straight-line segments projected onto the frequency axis fall on the pole and zero frequencies. The poles are sometimes called the cutoff frequencies of the network.

Which component in multisim generates a bode plot