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What does a Bode plot represent and what is a pole and zero of a Bode plot?

Bode plot Take a typical 2nd order low pass filter amplitude response bode plot: - 3-D picture introducing pole-zero diagram Here's the bigger picture of that response when combined with a pole ...
Andy aka's user avatar
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15 votes
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What is the difference between frequency response and transfer function?

A circuit's transfer function is a fully mathematical model that can be used to derive the frequency response and phase response (both together are called the bode plot). However the same isn't true ...
Andy aka's user avatar
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Why do we use step response?

Step response and transfer function are interchangeable via Laplace transform (step response -> differentiate to get impulse response -> laplace -> transfer function), but you can't run a Laplace ...
bobflux's user avatar
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14 votes
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Determine transfer function from circuit

When you deal with a circuit whose transfer function must be determined, you must try to rearrange the components and sources in a friendlier way so that things become clearer. For instance, in your ...
Verbal Kint's user avatar
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13 votes

How to find phase angle from transfer function

It is just a matter of manipulating complex numbers. $$ \angle H(\omega) = \tan^{-1} \left( \frac{\Im\{H(\omega)\}}{\Re\{H(\omega)\}} \right)$$ Where \$\Re \{ \cdot \} \$ is the real part and \$ \Im ...
rtclark's user avatar
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13 votes
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over and critically damped systems settling time

TL;DR: NO, you can't use the underdamped settling time formula to find out the settling time of an overdamped system. And you can't use it for a critically damped system either. LONG FORM answer ...
Enric Blanco's user avatar
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13 votes

Significance of cut-off frequency in a low-pass filter

H(w) =1/ (square root of 2) That sounds a bit confusing, we usually refer to the cutoff point as the -3 dB point. That is the same though, -3 dB is half the power. Let me explain: take your \$H(\...
Bimpelrekkie's user avatar
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Exciting an RC Circuit at its TRUE Pole on the Sigma (Real) Axis in the Left-Half Plane

Good question, here's my attempt. You still have to convert your input signal from the time domain to s domain, then do the math, then convert the result back to the time domain. That pole just tells ...
KD9PDP's user avatar
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10 votes
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Calculating magnitude of a transfer function

First off, we transform the s domain to frequency domain with \$s=j\omega \$ which gives us: $$T(j\omega) = \frac{1}{(j\omega+1)((j\omega)^2+j\omega+1)} = \frac{1}{(j\omega+1)(j\omega+1-\omega^2)} = \...
Ferry's user avatar
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Is every linear circuit equivalent to a single RLC series circuit?

Is every linear circuit equivalent to a single series RLC circuit? No. All passive linear circuits can be reduced to an order that is dependent on the number of independant storage elements. They can ...
RussellH's user avatar
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Poles of system seem counter intuitive

You have a pair of poles on the Y-axis. That is the abstract representation of an oscillator without damping. If your input is of finite duration, once the input goes to zero the oscillation will be ...
John Doty's user avatar
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Maximum Power Transfer Theorem Question

What you are missing is, that if you reduce your load to 1 ohm, it gets even more power: Total resistance: \$R_\text{tot}=R+R=1+1=2\text{ ohms}\$ Current: \$U/R_\text{tot} = 10\text{ V}/2\text{ ohms} ...
Sandro's user avatar
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9 votes
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Understanding in-loop compensation for capacitive-loaded OpAmp

I believe the authors used fast analytical circuits techniques or FACTs but I am not sure about their results. The principle is based on the generalized Extra-Element Theorem or EET from Dr. ...
Verbal Kint's user avatar
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9 votes

Is there an English word for the output response of a non-minimum phase system?

I've always heard that being called undershoot. And, in this Control Systems magazine article on Nonminimum-Phase Zeros they also call it initial undershoot.
jDAQ's user avatar
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8 votes
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Second order all-pass filter using a single op-amp

One option for a second order all-pass filter with one OpAmp is the Delyiannis structure, as shown here (p.2): The transfer function of this filter is given by $$H(s)=\frac{R_4}{R_3+R_4}\cdot \frac{...
Matt L.'s user avatar
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8 votes
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How can I build a circuit with this transfer function, using only resistors?

There are two problems with your design. A voltage divider only produces it's notional output voltage when unloaded. Your second stage forms an averaging circuit not a sum. Bottom line is that your ...
Peter Green's user avatar
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8 votes
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Op-amps circuit with diodes

You can analyse it in two conditions of input ui. When ui > 0 The op-amp output is positive and hence D1 will be forward biased and D2 will be reverse biased. Assuming ideal diodes and op-amps, we ...
Mitu Raj's user avatar
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8 votes
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Is there an English word for the output response of a non-minimum phase system?

I think the correct term in English would be “initial inverse response”. The system initially does the opposite of what is commanded. For example, in this book. So it’s even worse than a dead time ...
Spehro Pefhany's user avatar
8 votes
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I'm confused a bit on basic control stuff for a PID controller

Your control is quite good despite if you feel in other way. I do think that a P-control with feed forward LUT (Look Up Table) would solve 98% of your need. Try this way: For each temperature ...
Marko Buršič's user avatar
8 votes
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What is the definition of phase margin?

It's not the definition of phase margin. It's the way that "gain" in a control loop is defined. There's two systems of thought jostling together in the world of control theory, and neither ...
TimWescott's user avatar
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8 votes
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How can these passive RLC circuits change a sinusoid's frequency?

There is no loss in the system, therefore the startup transient continues oscillating forever. (Due to numerical errors in the transient simulator, it won't actually go forever.) The measurement is ...
Tim Williams's user avatar
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7 votes
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Transfer function of Bessel filter

How come that the transfer function in the TI design guide is not a Bessel polynomial. Let's look at the transfer function you have written: - \$H(s) = \dfrac{1}{0.618s^2+1.3617s+ 1}\$ Rearranging: - ...
Andy aka's user avatar
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7 votes

Transfer function of Bessel filter

A Bessel filter has, as you correctly show in your first formula, \$\omega_0=\sqrt{3}\$. It's not unusual if you think that, normally, a Bessel filter is used for its flat group delay, rather than its ...
a concerned citizen's user avatar
7 votes

Why do we use step response?

An impulse, i.e. hit it with a hammer, is not very friendly, particularly in systems that have mechanical bits and pieces. A perfect impulse cannot be generated, so you have to tailor the pulse ...
Chu's user avatar
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7 votes
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How to sketch the Bode diagram of the output filter of a Buck converter?

Background Starting with your result and proceeding: $$\begin{align*} H\left(s\right)&=\frac{R}{R\,L\,C\,s^2+L\,s+R}\\\\ &=\frac{1}{L\,C\,s^2+\frac LR\,s+1}\\\\ &=\frac{\frac 1 {L\,C}}{s^2+...
jonk's user avatar
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7 votes

Pole zero plot of band reject filter

Perhaps this is where the confusion starts: 's' is complex (re + j*im, or sigma + jw), not just imaginary. Those two terms are often accidentally used interchangeably, and they shouldn't be. G is ...
P2000's user avatar
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7 votes
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What are the final steps to arrive at the transfer function for this RCL circuit?

Your schematic is as follows: simulate this circuit – Schematic created using CircuitLab Above, you can see that \$R_2\$ and \$Z_2\$ form a voltage divider that divides \$V_Y\$ into \$V_\text{...
jonk's user avatar
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7 votes

How to find transfer function of this filter?

Early on, perhaps the best approach to solving complex-looking schematics is to figure out some way to divide them up into things you do recognize and can solve. Then break down each piece, repeating ...
jonk's user avatar
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7 votes
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Transfer function of an RLC filter

Your numerator in this: $$ v_{o}=v_{oi}\frac{R}{Ls+R_{L}+\frac{R(\frac{1}{Cs})}{R+\frac{1}{Cs}}} $$ Should be \$Z_R || Z_C\$. That is, $$ v_{o}=v_{oi}\frac{R || Z_C}{Z_L+R_{L}+(R||Z_C)} $$
ErikR's user avatar
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7 votes
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Flyback converter small-signal model

The answer given by Antonio51 is good and uses the auto-toggling CCM-DCM model built on the PWM switch in 2005. This is great to determine the small-signal response of many switching circuits and not ...
Verbal Kint's user avatar
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