# Questions tagged [loop-gain]

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### Op-amp inductive output impedance oscillation

In Learning the Art of Electronics pg.362, the author presents an op-amp follower driving a long cable. I don't understand the explanation given for the cause of oscillation. In particular, the author ...
• 1,167
130 views

### Drawing the Bode Plot of a loop gain

Below I have the loop gain and the Bode plot for it, however I do not understand the phase plot. Why does it start at -90 degrees instead of 90 degrees since we have a zero? Please explain.
• 191
165 views

### Estimate the phase margin of a loop gain

The loop gain is $10^6 /[(s+1)(1+s10^5)]$. Below I have the Bode plot. How can I derive the unity gain frequency from the Bode Plot? How can I find the phase margin from the phase plot of the Bode?
• 191
139 views

### How to find voltage gain of below analog circuit without using Nodal analysis?

This is a theoretical circuit just made to see that if I can find voltage gain of circuit and it took me much calculations then anticipated to get voltage gain.I just want to find if there is better ...
• 455
844 views

### Negative feedback and op-amp poles

I'm trying to get a better understanding of frequency compensation for op-amps. I'll start off with a very specific questions and then get into the context. For a certain op-amp, open loop gain is ...
• 15
538 views

### What's the largest practical stable gain possible?

I have a feedback application to set the voltage of a node in which there is considerable loss in the loop. Simulations tell me that a differential voltage gain of 10000, 80dB (roughly about what you ...
• 8,216
1 vote
97 views

### opamp simulation

Is the following open loop transient simulation of opamp correct ?
• 393
477 views

### Shunt Shunt Feedback SImulations

I am trying to simulate the solution to an old text book example on a simple Shunt-Shunt feedback amplifier. simulate this circuit – Schematic created using CircuitLab The book only shows BF = ...
• 31
1 vote
2k views

### Stability at loop gain <1 and 180 degree phase shift

I'm reading this article about stability of OpAmps: Link to article. It says: "If Aβ is less than unity at the high frequencies where phase shift reaches 180°, the high-frequency phase-shifted ...
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• 137
1 vote
950 views

### Why gain crossover frequency must be lower than phase crossover frequency for stable systems?

As far as I understood from here, phase margin means the amount of phase that needs to be added in order to coincide with 0 db gain and -180 degrees phase. Likewise for the gain margin it means means ...
• 213
103 views

### Why we can consider inductor as a current source when the current loop gain infinite?

I am reading about current-mode control from this site. Please look at the excerpt below and especially the boldfaced part. Question: Why we can consider inductor as a current source when the ...
• 1,517
1 vote