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LTspice ac analysis to determine stability of op-amp circuits
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mmilejski:
What about a video where Dave would show how to conduct an in depth analysis of some op-amp circuit prone to oscillation, including:
modeling test jig
an introduction to Bode plotting
common ways to reduce oscillation in op-amp circuits
using step function to choose right values for resistors and capacitors in feedback loop
I hope that is a good idea ;)
Maybe someone can post a link to existing video or document?
I already saw LT video on it, but it is short and does not explain Bode plots, just assumes viewer knows it.
Jay_Diddy_B:
Hi,
I have a look at his thread:
https://www.eevblog.com/forum/projects/dynamic-load-bode-plot-using-hp-35665a-dsa/msg309192/#msg309192
A Bode plot is the plot of the frequency response of a system versus frequency. The plot can show just amplitude or amplitude and phase.
The Bode plot is normally plotted with Log amplitude in dB on the y-axis and Log Frequency on the X-axis.
A single pole filter low pas filter will have a slope of -20dB per decade of frequency.
Bode plots are very effect for control loop analysis.
Before PCs, I used to solve control loop problems by drawing the various elements on Log-log paper.
Have a look at this:
http://en.wikipedia.org/wiki/Bode_plot
It is a bit over-the-top, in the mathematical department.
Regards,
Jay_Diddy_B
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