Activity for coquelicot
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #281540 |
@Joel Reyes Noche. Yes, I have a real AD8307, and I tried two from the five I've ordered. According to the datasheet (link in the question), output 4 is the "out" pin. (more) |
— | about 3 years ago |
| Comment | Post #281540 |
@Lundin. I don't know what is "spot market", but if that means "Chinese market", then yes. That question is also a way to know if I am understanding right the IC. (more) |
— | about 3 years ago |
| Comment | Post #281323 |
@Olin Lathrop. Thx for having pointing out this calculation mistake. What imported to me was the general idea, so I have not been careful. (more) |
— | about 3 years ago |
| Comment | Post #281325 |
@manassehKatz.
"The likelihood is that the breaker will trip and protect the people, devices and wiring involved quite well".
This is a strong claim!. (more) |
— | about 3 years ago |
| Comment | Post #281322 |
You first decided in the question that the resistance is high, which is relative and incorrectly stated at the least (as explained at the beginning of my answer). Then you say "water is a danger for short circuit" which may be interpreted in several ways, the most obvious one being: "Why is water con... (more) |
— | about 3 years ago |
| Comment | Post #281322 |
@Kranulis. Speaking about quality, the title of your question is "Why is the resistance of water so high?" (which is a physics question involving quantum mechanics), and inside the text, the question is "why water is such a danger for short circuits if the resistance is so high?", which is unrelated ... (more) |
— | about 3 years ago |
| Comment | Post #281323 |
@Kranulis. Unfortunately, my answer exactly answer to your question. So, if that not what you expected, you have not correctly asked the question. Also, you haven't pinpointed in what it does not go in line to what was asked, despite my answer is essentially similar to that of manassehKatz. This and ... (more) |
— | about 3 years ago |
| Comment | Post #281322 |
Just to let you know: in this site, it is not forbidden for a user to have several accounts, but it is strictly forbidden to use them for up-voting yourself, or even worse, to down-vote an answer by more than one point. (more) |
— | about 3 years ago |
| Comment | Post #281323 |
I gave you a -1 (my first one since I know this site) because if you estimate that my answer does not answer to your question, it is evident for me that your question is not correctly asked. (more) |
— | about 3 years ago |
| Comment | Post #281323 |
Your question is "why water is such a danger for short circuits", and I have given at least 3 reasons. (more) |
— | about 3 years ago |
| Comment | Post #281066 |
no 2. In what manner the higher required temperature affect the service life of the tip according to you? (more) |
— | about 3 years ago |
| Comment | Post #281083 |
For me, a schematic (or even a basic shema) would help. (more) |
— | about 3 years ago |
| Comment | Post #281059 |
@Lundin. Thank you for the link. I will have a look. (more) |
— | about 3 years ago |
| Comment | Post #281065 |
OK. See the add in my answer. (more) |
— | about 3 years ago |
| Comment | Post #281065 |
@mrwavelets. A communication signal IS a load. I think you should explain how the output of the modulated carrier wave is supposed to be used (do you want to feed an antenna with the signal?) (more) |
— | about 3 years ago |
| Comment | Post #281060 |
@Olin Lathrop. Thank you for your add, a strong argument indeed. In fact, I see no way the stray capacitance could be less than 1pF or so. Even if I keep only 1/20 of the signal, this requires an input impedance of 20 k Ohm at the best. I am doing research and research implies you try to discover som... (more) |
— | about 3 years ago |
| Comment | Post #281061 |
It is probable that the temperature of your soldering iron is too high. Try reducing the temperature (e.g. with a dimer), and see if this helps. (more) |
— | about 3 years ago |
| Comment | Post #281059 |
For the moment, I've found the opa695 that is best suited, but it has 70uA input current. Also, the big 50 Ohm load is a problem. (more) |
— | about 3 years ago |
| Comment | Post #281059 |
Not with those keywords. Will try and perhaps delete this question. (more) |
— | about 3 years ago |
| Comment | Post #280921 |
You should not connect the output for S11. For S21, you have to connect both terminals, but again, be careful to protect the VNA. (more) |
— | about 3 years ago |
| Comment | Post #280873 |
@Olin Lathrop. Thx for your answer. That's not me on the video, it's just a video showing the same GDO as mine, where the "emitter" function is used. I think you have rather described the "oscillating detector operation" of the dip meter. The "absorption wavemeter" is something simpler (https://en.wi... (more) |
— | about 3 years ago |
| Comment | Post #280870 |
@Olin Lathrop. A grid dip is a very well known device from the past, that is still used by radio ham. Google@grid dip to see tremendously many entries. I am not supposed to write an article here, sorry. Yet, since you say the question is unclear, I have added what I think that should be added to mak... (more) |
— | about 3 years ago |
| Comment | Post #280870 |
@Olin Lathrop. I've added a link to the full documentation where everything could be seen. I have to go work, but later, I will add pictures if necessary. (more) |
— | about 3 years ago |
| Comment | Post #280714 |
@Olin Lathrop. Thank you for this nice answer. I would like to precise my understanding (I don't think this is worthy a new question since the answer may be more or less "yes" or "no"). So, a measurement with a standard probe could be seen as the juxtaposition of a DC measurement with respect to the... (more) |
— | over 3 years ago |
| Comment | Post #280672 |
Have you think about making a stupid current source by hand: jfet + resistor, or npn + resistor + zener ? (more) |
— | over 3 years ago |
| Comment | Post #280578 |
Of course, this is a stupid diode in the other direction, but that's not what is needed in general for AC circuit (otherwise, use a diode). (more) |
— | over 3 years ago |
| Comment | Post #280152 |
Nice! a digital heterodyne! I much like this idea (+1). I will suggest you an edit for the Latex formula. Note: it's very easy to learn basic Tex/Latex typesetting (1h at most), and that's very useful in many circumstances and sites. (more) |
— | over 3 years ago |
| Comment | Post #280152 |
That seems to be an interesting trick. But I don't understand how a XOR can produce a triangle wave. According to my very limited knowledge of digital electronics, there is a low and high state. How does that produce the intermediate states of the triangle wave? or are you using the RC network to thi... (more) |
— | over 3 years ago |
| Comment | Post #279966 |
@Olin. Your answer is again fascinating: 1. why may the modest resistor inside the loop lead to instability? and 2. (probably related) could you explain how the cap solve this problem (I've never seen this technique). If the cap were connected after the resistor, I would say it improves the high freq... (more) |
— | over 3 years ago |
| Comment | Post #278933 |
For example, regulating the voltage with the battery as a voltage reference is bad in general, and using the base of the transistor to pass the backup current is bad design as well. Also, charging the battery this way is bad. At the price of few basic added components, you can do everything right. Yo... (more) |
— | over 3 years ago |
| Comment | Post #278933 |
@circuit fantasist. That means a man building things not rigorously, in order for it to work in the given case, but not according the EE rules of the art. A good electric engineer would never have done that this way. /continued (more) |
— | over 3 years ago |
| Comment | Post #279733 |
Well, you asked as if there a superior architecture approach, so I answered to that. (more) |
— | over 3 years ago |
| Comment | Post #279431 |
@Circuit fantasist. The most banal 3$ digital multimeters like the ones in the OP question have at least 1M ohm input impedance, more for more expensive voltmeters. So, this is pointless. (more) |
— | over 3 years ago |
| Comment | Post #279228 |
@TonyStewart. What is calibrated torque? (more) |
— | over 3 years ago |
| Comment | Post #279280 |
I am always surprised I get downvotes for such questions: someone disagrees with this question ???????????????
someone hate me ??????????????? (more) |
— | over 3 years ago |
| Comment | Post #279250 |
@Lundin. I may have misunderstood your point. Are you suggesting to replace only the bullets mentioned in your question, or to replace the whole page? (more) |
— | over 3 years ago |
| Comment | Post #279227 |
@Andy. Actually, in my answer, the analyzer output impedance of 50 ohm I've assumed and added inside the schematics (to the left) plays no role: everything is function of U1 alone, and the same results would hold if the output impedance at the s11 terminal had been something else. I think this impeda... (more) |
— | over 3 years ago |
| Comment | Post #279227 |
@Andy. Actually, our answers do not coincide for s21. You say that the expected s21 should be 0.5, but I've computed it should be 0.66... as indicated by the analyzer. Is there some mistake in my answer or yours? (more) |
— | over 3 years ago |
| Comment | Post #279227 |
Note: Actually, the analyzer displayed -9.28db at the marker position, as can be hardly seen (a ratio of 0.3435). I've incorrectly approximated with -9db in the question. (more) |
— | over 3 years ago |
| Comment | Post #279227 |
And as always, where I have to spend hours to understand the math, you just feel things, and you feel them right. (more) |
— | over 3 years ago |
| Comment | Post #279227 |
@Andy, we have written answers in parallel. I'm happy to see that your condensed answer coincides with mine. (more) |
— | over 3 years ago |
| Comment | Post #279080 |
@Lundin. Admittedly, the "thing" looks bad, worse than it really is, because there are reflections and other image artifacts. But I am sure there is no short. I may do a more pretty circuit and post it this week when I am in my lab. On the other hand, if you already know how the s11 and s21 SHOULD lo... (more) |
— | over 3 years ago |
| Comment | Post #279016 |
@circuit fantasist. After your updates, I now like this article. (more) |
— | over 3 years ago |
| Comment | Post #279050 |
@circuit fantasist. Yeah, as you could see, I've deleted my previous comment yesterday, where I said the Art of Electronics does not deal with this subject. On the contrary, the authors deal extensively with that. How have I missed that? I don't know but I am now studying this part thoroughly· (more) |
— | over 3 years ago |
| Comment | Post #279030 |
+1 for having pointing out that FET followers can be used advantageously to buffer small signals, where usually, only the AC part matters. They provide a nearly infinite input impedance to the signal, and the output can be passed through a cap. Good catch!
N.B: To present nicely math formulas, e... (more) |
— | over 3 years ago |
| Comment | Post #279018 |
You are right, I'll fix that. (more) |
— | over 3 years ago |
| Comment | Post #279016 |
I am not against the pot, but I think this should be written somewhere, preferably inside the schematic, something like: "light intensity signal simulated with potentiometer P" near the pot.
Regarding the schematics, I think adding the current loops in green is more than sufficient. The voltage dro... (more) |
— | over 3 years ago |
| Comment | Post #279016 |
@Circuit fantasist. I do not disagree that the pot is a good way of testing your circuit, but it is a fact that this makes your article difficult to follow. It took me a while to understand what the circuit is supposed to do!!!! You have only given a short hint as a historical account at the beginnin... (more) |
— | over 3 years ago |
| Comment | Post #279022 |
@Olin Lathrop. Thank you for your answer. So, should I understand it as : No use of FET followers in electrical engineering? Edit: I reformulate this question: do you see any reason to use a FET follower ?
(more) |
— | over 3 years ago |
| Comment | Post #279016 |
Basically, it could be a good article and I find it interesting, more interesting than your previous articles. The only reasons I've not upvoted it are explained just above. (more) |
— | over 3 years ago |
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