Activity for Olin Lathropâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #284936 |
I understand the units are mislabeled in the diagram, which is not under your control. However, you continued the sloppiness with units in your own text. You should have written (1 m)/c instead of 1/c. Units matter. (more) |
— | over 2 years ago |
| Comment | Post #284538 |
You can think of it that way. With the base voltage held constant, the transistor itself produces more emitter current when the emitter voltage drops. (more) |
— | over 2 years ago |
| Comment | Post #284562 |
You've done this a bunch of times now, where you don't put a space after the period or question mark at the end of the sentence. Several times others have fixed it for you. We're not going to keep doing that. It's rude to continue throwing slop at us like that, especially after it has been pointed... (more) |
— | over 2 years ago |
| Comment | Post #284514 |
Explain how you think how the circuit works. In particular, I want to know what you think R3 does, and why it has the value it does.
Remember, we don't just answer homework questions here. We can help you thru the process or understanding a circuit, but that requires you to actively participate.... (more) |
— | over 2 years ago |
| Comment | Post #284514 |
You ask about feedback and gain. These make no sense without an input and output. Gain can only be from one specific place to another specific place. Don't be so sloppy. Also, tell us how you tried to solve this problem and where exactly you are stuck. (more) |
— | over 2 years ago |
| Comment | Post #284282 |
This site has a wide audience, so you should define, or at the very least spell out PMSM and VFD. I know what they stand for, but if you spelled them out, particularly PMSM, you might notice yourself that PMSM and AC induction motor don't make sense together.
Step back and explain in more detail ... (more) |
— | over 2 years ago |
| Comment | Post #284253 |
@Joel: "parallel plate inductor" doesn't make much sense. (more) |
— | over 2 years ago |
| Comment | Post #283936 |
While you are technically correct, I think you're also being pedantic in this case. Given that there is no such thing as an ideal current source in reality, it seems clear enough that the switch and current source together are meant to be an open when the switch is open, and producing a fixed curren... (more) |
— | over 2 years ago |
| Comment | Post #284253 |
I read this twice and still don't know what your setup is and what exactly you are asking. You start out talking about a parallel plate capacitor. OK so far. But in the next paragraph there is something about an inductor, but that was not previously defined or introduced.
We can't know the assu... (more) |
— | over 2 years ago |
| Comment | Post #284219 |
That's much better, and I wouldn't have closed it in its current state. However, since we're here, fix it the rest of the way. The junction dot to the right of C1 and below R4 is missing, V1 could be centered better, etc. Show me an example of neatness and attention to detail! Actually *try* to m... (more) |
— | over 2 years ago |
| Comment | Post #284219 |
That schematic is too much of a mess to look at. There are too many unnecessary zig-zags, gratuitous "loopy" corners, and rails that are not straight. Asking others to look at this mess is downright rude. It is like writing two paragraphs in text-speek.
You've had plenty of warnings about slopp... (more) |
— | over 2 years ago |
| Comment | Post #284199 |
@Kran: Some questions *are* stupid. The OP isn't going to change without some reaction to that. In any case, if you think a question isn't answered well, write your own answer. We could use more good answers here, in addition to more questions. This site won't go anywhere if one person does most ... (more) |
— | over 2 years ago |
| Comment | Post #284199 |
@Kran: Yeah, these questions have been pretty lazy. I haven't been upvoting the lazy ones, and sometimes downvoting. We want to help students, but we also aren't here to read the datasheet to people. At this point in the life of this site, I'm being more tolerant and using these questions as a way... (more) |
— | over 2 years ago |
| Comment | Post #284207 |
There were two flags to close this question. I'm not going to close it, but don't be so lazy. This is almost certainly why you are getting downvotes. Look at a few datasheets yourself. If you don't understand what the datasheets are saying, then ask about that. (more) |
— | over 2 years ago |
| Comment | Post #284076 |
@Carl: Self-answered questions are allowed here. Of course a self-answered question should be the kind that someone else might reasonably run into, and both the question and answer must be well written, well presented, and correct. (more) |
— | over 2 years ago |
| Comment | Post #284074 |
Asking for the voltage of a "circuit" is meaningless. It's obviously 0 around any closed loop. It would make sense to ask about the voltage between two specific points, or across a specific component. (more) |
— | over 2 years ago |
| Comment | Post #283958 |
OK, but don't tell me here, <i>fix the question</i>. (more) |
— | over 2 years ago |
| Comment | Post #283958 |
How coupling effects the series inductance is a good question, +1. However, it's ambiguous to talk about the inductance "of this circuit". Do you really mean the two inductors in series? Do you mean the inductors and resistor as view from the voltage source? (more) |
— | over 2 years ago |
| Comment | Post #283956 |
No, 2(4/9) <b>is</b> dimensionless. That's what you wrote. (more) |
— | over 2 years ago |
| Comment | Post #283956 |
Seriously!? Just read the whole post looking for errors. Obviously you haven't done this yet. (more) |
— | over 2 years ago |
| Comment | Post #283956 |
Whether one can guess the units is not the point. It's still <b>just plain wrong</b> to equate a value of Volts to a dimensionless quantity. (more) |
— | over 2 years ago |
| Comment | Post #283956 |
I've said this before, so this time you get a -1 right away. We do engineering here, where units are important. Every numeric value that is not dimensionless <i>must</i> be shown with its unit. Units must match on opposite sides of every equals sign. If not, the equation is wrong, just like if th... (more) |
— | over 2 years ago |
| Comment | Post #283955 |
Much better schematic, +1. (more) |
— | over 2 years ago |
| Comment | Post #283956 |
There several errors because it seems you copied and pasted this answer from your answer to a similar question about an inductor. You should carefully read over the whole post before posting, then sometimes again a while after posting. That will catch a lot of this sloppiness. (more) |
— | over 2 years ago |
| Comment | Post #283936 |
Why would I want to do that? As far as I can tell, it answers the question correctly. What do you think is wrong? (more) |
— | over 2 years ago |
| Comment | Post #283926 |
I told you before, always include component designators on your schematic. -1 for ignoring this requirement. Ping me when you fix it, and I'll undo the downvote. (more) |
— | over 2 years ago |
| Comment | Post #283906 |
Oops. Yes, I meant to say "minimum". (more) |
— | over 2 years ago |
| Comment | Post #283904 |
The equation you use that implies the LED current as a function of the voltage across it is stated nowhere in the datasheet. You should only go by what it says in the datasheet. Also 5 digits is absurd in this case, especially due to the high temperature dependence of LEDs in general. "295.05 &Ome... (more) |
— | over 2 years ago |
| Comment | Post #283906 |
The general form of this answer is correct, +1. However, you shouldn't be using the typical forward voltage drop, but the worst case (highest) for the current you want. The resulting calculation that you show than results in the <i>minimum</i> resistance to not exceed the maximum current rating of ... (more) |
— | over 2 years ago |
| Comment | Post #283361 |
I don't know. I thought it was a reasonable question and upvoted it. It is unfortunate that users can downvote something anonymously and without explanation. (more) |
— | over 2 years ago |
| Comment | Post #282848 |
Please don't include the disclaimers that you show. It's your personal content, so you can use it here too without it being plagiarism. As for stating that the answer is made up, that just adds noise. Someone with that problem looking for the answer isn't going to care. Everyone can see that the ... (more) |
— | almost 3 years ago |
| Comment | Post #282672 |
@Kranulis: While we do give some extra slack, ultimately we don't tolerate lazy students or sloppy engineering just because this site is still young. If this site had high traffic, this question (and probably a few others with the same crayon schematics) would have simply been closed and forgotten. ... (more) |
— | almost 3 years ago |
| Comment | Post #282711 |
This question is too broad in its current form. Show a circuit of what you call a "unbalanced frequency mixer", and we can probably explain how it works. Or, give a proper spec for what this circuit is supposed to do, and we might be able to show how diodes could be used to advantage. (more) |
— | almost 3 years ago |
| Comment | Post #282585 |
Hmm. It's still pretty hard to read. What's that thing in the top middle of the schematic, for example? Also, the equations in your text are unreadable. We have MathJax here for that. I'll reopen it this one time, but in the future this won't be good enough. You wouldn't hand in homework this i... (more) |
— | almost 3 years ago |
| Comment | Post #282585 |
This question is closed because the diagrams are unreadable. You should have been able to see that for yourself. Each circuit should probably be a separate image, and any text between should be normal text in the question. Text in images doesn't work for indexing and searching. While you're at it... (more) |
— | almost 3 years ago |
| Comment | Post #282572 |
You say the electronics needs 4 A at 12 V, and that it has been redesigned to use "up to" 48 V. Can it still run from 12 V? You say one option is to increase the 12 V to "48V and 4A". Does the new redesigned circuit now require 4x the power? Why not 48 V and 1 A? (more) |
— | almost 3 years ago |
| Comment | Post #282265 |
@Carloc: If you feel something is wrong and downvote, the author really deserves an explanation unless it's just a crackpost post (which I think we can agree is not the case here). That way the author knows what to address and who to ping in case the error is fixed (so that the downvoter can undo th... (more) |
— | almost 3 years ago |
| Comment | Post #282288 |
Why was this downvoted? The author has clearly put some effort into this answer. If he got something wrong, then he should at least be given the courtesy of being told what that is. Sorry I can't help here. These battery details are beyond my expertise, so I'm not voting either way. (more) |
— | almost 3 years ago |
| Comment | Post #282265 |
Why did this get downvoted? (more) |
— | almost 3 years ago |
| Comment | Post #282194 |
@Dave: Good point. You should write an answer with that. Another way of looking at this is that the equation of capacitor voltage as a function of driving voltage will have a state variable. That state variable represents the charge on the capacitor. (more) |
— | almost 3 years ago |
| Comment | Post #282160 |
@leventov: There are so many opinions out there, it's way beyond us to judge which are best. We leave the presentation to the authors. The help only tries to give guidance on what the content and level of detail of a paper should be. (more) |
— | almost 3 years ago |
| Comment | Post #282160 |
@manass: I agree that a writeup about driving LEDs would make a good paper, as long as the detail is sufficient, and the underlying theory is explained. The equivalent of two printed pages would probably be a good minimum length. (more) |
— | almost 3 years ago |
| Comment | Post #282154 |
I don't know what you mean by "kinetic" in this context. Surely you don't mean the inertia of ions travelling thru the electrolyte. There is a significant voltage step from charging a cell at 1C, to immediately after disconnecting the cell. In other words, the cell exhibits some effective series r... (more) |
— | almost 3 years ago |
| Comment | Post #282154 |
@coquelicot: The inner workings of electrical components is on-topic here. I don't know how many people that visit here have the expertise to answer this question, though. Most of it is over my head. It would be good to have some electro-chemical experts here. (more) |
— | almost 3 years ago |
| Comment | Post #282053 |
@Lundin: Actually the right kind of box doesn't need to be large. The walls can be in the near field as long as they appear as more space to the antenna. There are actually RF boxes built on this principle. You need just the right ferrite tiles so that the walls have the same 377 Ω impedance... (more) |
— | almost 3 years ago |
| Comment | Post #282053 |
@Lundin: No, a "metal box" around an antenna would have a major effect on the antenna if in the near field, and would reflect the signal from the antenna back on itself if in the far field. If that metal box were lined with ferrite tiles, then it can work at some frequencies. You have to carefully ... (more) |
— | almost 3 years ago |
| Comment | Post #281549 |
@coq: It is not evident at all how pins are connected when not shown. To show an unconnected pin, show it with nothing connected. The quality of a question is *always* relevant. When volunteering, it is totally the volunteer's call as to what constitutes wasting of time. (more) |
— | about 3 years ago |
| Comment | Post #281478 |
The title asks about input capacitance, but then the body seems to be asking about a power filter capacitor. What are you really asking, and what is a "BLDC inverter"? BLDC is common for "brushless DC" motor. Do you mean a controller or driver for such a motor? What is "inverter" supposed to tell... (more) |
— | about 3 years ago |
| Comment | Post #281444 |
@Kran: My point is that it doesn't matter either way if the design was tweaked experimentally until it produced the desired result. Square versus curved is then just an implementation detail. (more) |
— | about 3 years ago |
| Comment | Post #281364 |
@Mu3: Remember that the FET likely has a body diode. (more) |
— | about 3 years ago |