Hello Sam Ben, I am glad to hear from you, I understand that I am not talking about the subject of electronics, I am very aware of everything that is happening and worries me, I just want to thank you for everything you do and also wish you the best, you are a Great Person, I value him a lot, I send him a Big Hug...Gracias !!!! ,🙏🙏🙏🙏
Happy to hear from you Professor, wish you the best, hope these conflicts come to an end where all people live peacefully, thank you for your time and video
Hello! An important question. Is this analysis only for voltage amplifier cases? How would this apply to TIA amplifier case in LTspice? I want to see if a photodiode in photovoltaic mode(no bias) with an opamp is stable or not. Will it be done same way as -V(out)/V(FB) in TIA case?
I might be a bit rusty on my control theory, but isn't this case called a conditionally stable system? As shown here its very stable, as that phase wiggle is very far from crossover point - move it closer and you'll see damped oscillation - its sorta stable, but sorta oscillates. I also don't get where the misconception arises - AFAIR by definition its not what phase does in general, but what phase does WHEN gain crosses zero, at least this is how I learned it and you've demonstrated it on the unity circle.
Hello dear Professor, I hope you and your family members are ok and doing well. I can't believe even in this difficult time you are preparing and uploading videos. God bless you abundantly ❤
Thanks for comment and concern. As it occurred so many times in the past to our people, we will prevail this terrible and savage atrocities too, and will continue to contribute to society.
Thank you for this very clear explaination of the phenomenon that confused mi mind for a very long time, can you indicate me where you explain the small signal analysis for the stability?
I am still perplexed. I understand if LG equals to 1, we'll have 1 - LG = 0 in the denominator and anything other would give a non-zero value, but common sense is telling me if the phase is 180 degrees, and gain is greater or equal to 1 the circuit would overshoot (at 200 mHz on the graph). Your math is certainly right, and it is me getting something wrong. Why it does not happen in the practice?
@@sambenyaakovThank you for a very interesting lecture ( as are all of your lectures). So does your explanation mean that for stability we only care about phase margin? And Gain Margin is not important? In your example with added phase shift we clearly not meeting Gain margin criteria for stability
@@megfvvd35432 OK. Let me clarify. I was referring to instability in the sense of oscillations. I did not discuss in this video the effect of phase margin and gain margin that may cause overshoots. Thanks for conversation.
interesting , maybe it is better top go worth a log scale in the nyquest diagram , asking since in a way it is hard to figure out how that drop in phase looks like , also this in a way opens up some more higher order filtering for SMPS with odd phase shifts at certain gains
@@sambenyaakov hmm then maybe with some programmable voltage sources but I am not sure how practical it is. Maybe exporting data to cover and doing it in another program.
Hello Sam Ben, I am glad to hear from you, I understand that I am not talking about the subject of electronics, I am very aware of everything that is happening and worries me, I just want to thank you for everything you do and also wish you the best, you are a Great Person, I value him a lot, I send him a Big Hug...Gracias !!!! ,🙏🙏🙏🙏
Thanks for comment and concern. I and family are OK.
Happy to hear from you Professor, wish you the best, hope these conflicts come to an end where all people live peacefully, thank you for your time and video
Thanks for comment and concern. I and family are OK.
Hello! An important question. Is this analysis only for voltage amplifier cases? How would this apply to TIA amplifier case in LTspice? I want to see if a photodiode in photovoltaic mode(no bias) with an opamp is stable or not. Will it be done same way as -V(out)/V(FB) in TIA case?
Same way but you need to get the loop gain. What is -V(out)/V(FB) from where to where?
I might be a bit rusty on my control theory, but isn't this case called a conditionally stable system?
As shown here its very stable, as that phase wiggle is very far from crossover point - move it closer and you'll see damped oscillation - its sorta stable, but sorta oscillates.
I also don't get where the misconception arises - AFAIR by definition its not what phase does in general, but what phase does WHEN gain crosses zero, at least this is how I learned it and you've demonstrated it on the unity circle.
The video is meant for people that don't know it all😊
Hello dear Professor, I hope you and your family members are ok and doing well. I can't believe even in this difficult time you are preparing and uploading videos. God bless you abundantly ❤
Thanks for comment and concern. As it occurred so many times in the past to our people, we will prevail this terrible and savage atrocities too, and will continue to contribute to society.
Ok this is a very interesting new dimension of understanding the nyquist plot.
👍🙏
Hey Professor, can phase lag be also thought of as a signal delay?
Absolutely, including digital sampling inherent delay.
Thank you for this very clear explaination of the phenomenon that confused mi mind for a very long time, can you indicate me where you explain the small signal analysis for the stability?
This IS small signal analysis. Or I miss something?
I am still perplexed. I understand if LG equals to 1, we'll have 1 - LG = 0 in the denominator and anything other would give a non-zero value, but common sense is telling me if the phase is 180 degrees, and gain is greater or equal to 1 the circuit would overshoot (at 200 mHz on the graph). Your math is certainly right, and it is me getting something wrong. Why it does not happen in the practice?
Thanks for comment. One more time that commonsense is misleading. Like predicting humans behavior😊
@@sambenyaakovThank you for a very interesting lecture ( as are all of your lectures). So does your explanation mean that for stability we only care about phase margin? And Gain Margin is not important? In your example with added phase shift we clearly not meeting Gain margin criteria for stability
@@megfvvd35432 OK. Let me clarify. I was referring to instability in the sense of oscillations. I did not discuss in this video the effect of phase margin and gain margin that may cause overshoots. Thanks for conversation.
interesting , maybe it is better top go worth a log scale in the nyquest diagram , asking since in a way it is hard to figure out how that drop in phase looks like , also this in a way opens up some more higher order filtering for SMPS with odd phase shifts at certain gains
LTspice does not support log scale in this mode.
@@sambenyaakov hmm then maybe with some programmable voltage sources but I am not sure how practical it is. Maybe exporting data to cover and doing it in another program.
@@sanjikaneki6226 Zooming tells it all.
Proffessor your videos are great ... I'm a PhD student in power electronics... would like to connect with you in future if possible for sure
Sure.