Activity for coquelicot
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #278604 |
@Circuit fantasist. Basically, I like your point to present and explain electronics from another angle; unfortunately it's an art and a gift given to few persons. When I was teaching math at the university, I thought once to do something similar; this was a fiasco, and that made me understand why the... (more) |
— | over 3 years ago |
| Comment | Post #278475 |
Sounds like I made everyone angry, by trying to improve things. What a mess! definitely too much for me, I leave. (more) |
— | over 3 years ago |
| Comment | Post #278475 |
@Andy. If you wish, you can do the following experiment: take an ordinary computer PSU and try to filter the noise at the output. You'll see.
Regarding your other remarks, I will think about. (more) |
— | over 3 years ago |
| Comment | Post #278475 |
@Andy. This contradicts my experiments. Sure, in theory, you are right: ground is ground. But in my experiments on desktop computer ATX PSUs, I've observed that ground is a fiction. These PSU are so inherently noisy in the high frequency range that a common mode noise arrive SOMEHOW to the terminals ... (more) |
— | over 3 years ago |
| Comment | Post #278477 |
@Andy, as I said, I was in the darkness. I felt that at some point, when I said "let's leave that". I've edited the 3 last lines of my question to be fair with the answer of Olin. Hope this is more acceptable. (more) |
— | over 3 years ago |
| Edit | Post #278475 |
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— | over 3 years ago |
| Comment | Post #278477 |
@Olin. Please, consider deleting your last edit, or delete the whole post if you wish: This degrades unfairly your answer that was perfectly valid in my point of view. (more) |
— | over 3 years ago |
| Comment | Post #278477 |
@Olin. You are completely wrong, your answer is a legitimate answer to my question, and I'm sad you feel like this. I've edited my question to focus on that particular point because Andy asked me to do that, and because it is not dealt in your answer (that's the ironic point). I was vaguely aware tha... (more) |
— | over 3 years ago |
| Edit | Post #278475 |
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— | over 3 years ago |
| Comment | Post #278475 |
@Andy. See my edit. (more) |
— | over 3 years ago |
| Edit | Post #278475 |
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— | over 3 years ago |
| Comment | Post #278477 |
So, your answer is nothing, or at most a linear post-regulator. I thought there is more than that but OK. (more) |
— | over 3 years ago |
| Edit | Post #278475 |
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— | over 3 years ago |
| Edit | Post #278475 |
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— | over 3 years ago |
| Edit | Post #278475 |
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— | over 3 years ago |
| Edit | Post #278475 | Initial revision | — | over 3 years ago |
| Question | — |
Filtering the high frequency noise in switching PSU It is well known that it is difficult to filter the noise generated by switching power supplies, and this difficulty increases as the PSU is supposed to deliver large currents. For example, in a usual LC filter, the self may reach the saturation if a large current is passing through. I would l... (more) |
— | over 3 years ago |
| Comment | Post #278417 |
I am currently doing research about biological effects involving high voltage, magnetic fields and microwaves. My aim is to demonstrate the effect with a prototype and then to create a startup. So, I develop my projects dynamically, and I just anticipated that micro controllers may be a useful tool i... (more) |
— | over 3 years ago |
| Comment | Post #278465 |
@Olin. Always a pleasure to read the masters. Could you elaborate a bit about "At high frequencies, the return currents in the ground plane actually follow the path of the outgoing currents in X and Y etc." it's not very clear to my mind of poor mortal. (more) |
— | over 3 years ago |
| Comment | Post #278421 |
@Lundin. My common sense says this is not a matter of war, it's all about money. True professionals always want to minimize the price of their products, and choose the cheapest micro controller that can fit the required task (is ARM cheaper than all what exists on the market ?). So, what Olin says ma... (more) |
— | over 3 years ago |
| Comment | Post #278421 |
@Olin. Your reaction to the answer of Lundin is again instructive for me (thx). Of course, I knew his opinion about Raspberry an Arduino was a bit extremist, as you can understand from my humorous comment. Yet, I think his answer contains very good things. Also, I believe when he says that Modern 32 ... (more) |
— | over 3 years ago |
| Comment | Post #278421 |
@Lundin. Thank you so many for your help and comments. Things are now much clearer for me. (more) |
— | over 3 years ago |
| Comment | Post #278421 |
@Olin thx. I am now convinced that I should use micro controllers. The problem is there is no general purpose one (according to the answers here). This makes things even more complicated for me. Regarding the "moderator note", I don't know what to do about that: do you want I edit the question (thi... (more) |
— | over 3 years ago |
| Comment | Post #278420 |
Wow, now the situation is even more complicated for me; you killed my hopes (a chance that I was not depressive today, otherwise you would have killed me too :-) ). +1 and thanks for this really good and elaborated answer. (more) |
— | over 3 years ago |
| Comment | Post #278355 |
@Lundin. You say a Schottky from Vout to Vin. I did put a normal diode between Vout to Vin but this did not prevent the part to fry. Do you think a Schottky better protects the part than a normal diode ? (more) |
— | over 3 years ago |
| Edit | Post #278417 |
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— | over 3 years ago |
| Edit | Post #278417 | Initial revision | — | over 3 years ago |
| Question | — |
I have to choose: Arduino or Raspberry pi. Moderator Note If this site were mature, this question would be closed because it solicits opinions, or is too specific about particular models. In the interest of site activity, answers are being allowed that compare and contrast microprocessors boards to microcontroller development boards in ge... (more) |
— | over 3 years ago |
| Edit | Post #278354 |
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— | over 3 years ago |
| Edit | Post #278354 |
Post edited: complete reediting, following the comment of Olin. |
— | over 3 years ago |
| Comment | Post #278354 |
@Olin. The circuit I showed was only an illustration of what is a usual return path to ground (see the ":" before the image). The bootstrap technique is already illustrated by the images in the question and in your answer. I'll probably take into account your remark and edit this answer though. (more) |
— | over 3 years ago |
| Edit | Post #278355 |
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— | over 3 years ago |
| Edit | Post #278355 |
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— | over 3 years ago |
| Edit | Post #278355 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Is ESD overhyped? Just to let you know: if one day you have to use the LM337 negative voltage regulator, protect everything with TVS or Zeners. This is the most failing component I've ever seen (and I'm not the only one who thinks so, see youtube). I suspect strongly it is very sensitive to ESD. In my last application... (more) |
— | over 3 years ago |
| Edit | Post #278354 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Design rules for opamp bootstrapping I answer to myself because I believe this subject is interesting and not very well understood, even to professionals. Also, I want to point out that this answer is the product of my own investigations and simulations, and is not coming from reliable sources or knowledge. First of all, I want to p... (more) |
— | over 3 years ago |
| Comment | Post #278344 |
Thank you for your answer Andy. Curiously, this is more or less what I tried to do. But I think this time, Olin was right: there is a limit of what is possible to do with analog electronics: Even a 9th order elliptic filter would not give me the required spec. Only a Fourier transform performed on a ... (more) |
— | over 3 years ago |
| Comment | Post #278193 |
@Olin. The field mill is interesting and I was unaware of it. But as far as I understand, it is not well suited to my needs (especially its physical aspect). The electrostatic field meter I've conceived and built is interesting because it is extremely simple and handy, can give very precise measureme... (more) |
— | over 3 years ago |
| Comment | Post #278193 |
@Olin. Thank you for having updating your answer. Of course, I was perfectly aware that with a faster rotation speed, I could filter the noise easily. Unfortunately, my budget is restricted and I do everything by myself. In particular, I have to cope with the material I have in my lab: Modifying the ... (more) |
— | over 3 years ago |
| Comment | Post #278193 |
@Lundin. Thank you for helping me. The power supply is two 9V batteries inside a metal box (all the electronics is included inside the box to avoid main pickup, and the wire to the probe is a USB shielded wire). The problem is not the noise from the power supply, but the noise picked up by the extrem... (more) |
— | over 3 years ago |
| Comment | Post #278193 |
@olin. Thank you for trying to help me. Indeed, the 50-60Hz noise comes from ambiant capacitive coupling of my fieldmeter probe with the near power lines. Unfortunately, I have to amplify the tiny signal out of the probe and the noise is amplified as well. The fieldmeter works very well, but the 50Hz... (more) |
— | over 3 years ago |
| Edit | Post #278192 |
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— | over 3 years ago |
| Comment | Post #278192 |
Regarding currents, see my edit, no (4). Regarding the bandpass filter, I think it is always more complex than a high pass filter, so I've not precised that. But if that can help, I don't need more than 110 Hz (that is, the band would be 90Hz-110Hz). (more) |
— | over 3 years ago |
| Edit | Post #278192 |
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— | over 3 years ago |
| Edit | Post #278192 |
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— | over 3 years ago |
| Edit | Post #278192 | Initial revision | — | over 3 years ago |
| Question | — |
High pass filter design Despite there are many filter calculators available on the web, I still have difficulties to translate what I need into calculator design parameters. For my application, I need ideally a high pass filter that kill everything below 60Hz, and keep everything near 100Hz. More mathematically, I would... (more) |
— | over 3 years ago |
| Comment | Post #278066 |
@Olin. Regarding "What is the amplitude of the sine generator output? That divided by 200 kΩ should be the current out of the sine generator with C1 removed." This is what occurs: 1V / 200 KOhm = 5uA. That is, I may have confused you when I said "as previously", I meant "as in the previous simulation... (more) |
— | over 3 years ago |
| Comment | Post #278066 |
@Olin, I have serious doubts regarding the capability of LT spice to simulate faithfully the behavior of oamps. Thinking about, I'm not certain that this simulation has to be taken too seriously. This may explain some incoherences. (more) |
— | over 3 years ago |