John Dunn is an electronics consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York University (MSEE). This article was originally published on EDN. 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. 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. High-Pass Filter The Multisim computer analysis is an investigation of the high-pass filter in Fig. 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. I used one microvolt peak for V2 and fed that to the top of R3 via one teraohm. Simulation mode to generate, as its name implies, Bode Plots. (It’s fun when you can anthropomorphize an inanimate thing, isn’t it?) Multisim actually has an instrument called the Bode Plotter which is used in the Interactive. I had to add V2 and R4 as shown in Figure 2 to serve as an external stimulus to convince the Bode Plotter to do its thing. The Bode Plotter would not accept the oscillator’s own oscillation as the circuit excitation. However, when I tried to use the Bode Plotter on the oscillator circuit itself, there was no response, even though the oscillator was working and delivering signal. The signal source V1 provided the circuit excitation required by the Bode Plotter tool to get that instrument to function. Using a Bode Plotter on the passive component network alone, I saw what I was hoping to see: a sharp peak in the transfer function at the correct frequency-in this case at approximately 1.6MHz. 《MOTIX™ Multi-MOSFET Driver: Best-in-Class Solution for DC Motor Control》📢To control up to eight half-bridges with one packaged deviceįigure 1 An unsuccessful analysis attempt.

Bode plots in multisim