Activity for Nick Alexeev
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #291386 |
@#53469 Only the position of the dots relative to each-other matters. If both dots are on the same side, then it's a common mode choke (both on the left side, or both on the right side, doesn't matter which side). If one dot were on the right and another one on the left, then it would be a differe... (more) |
— | about 17 hours ago |
| Comment | Post #291238 |
Component ID question questions have to meet certain guidelines. Here’s our [present version of the guideline](https://electrical.codidact.com/help/compid). EE.Codidact isn’t inundated by identification and repair questions, and that’s not a bad thing. After some number of such questions accumulat... (more) |
— | about 1 month ago |
| Comment | Post #291238 |
@#53279 Check the output of the unidentified 331 chip on the undamaged unit. Probe the voltage at the middle pin, and at the other tantalum capacitor (the East-West one). It may be a boost switcher. That would explain two things: the connection of the inductor, the diode between pins 2 and 3. If... (more) |
— | about 1 month ago |
| Comment | Post #291240 |
Yes, that’s a SOT-89. I looked up switch mode regulators [with integrated MOSFET] on DigiKey, and there are none in SOT-89. Maybe it’s a linear regulator, or a transistor. (more) |
— | about 1 month ago |
| Comment | Post #291238 |
@#53279 There are two throughole pads south of these parts in this photo. They are marked [-] and [+] in copper. It looks like wires are soldered there. What's the purpose of these terminals? What's connected to them? (more) |
— | about 1 month ago |
| Comment | Post #290863 |
Fixing these problems may reverse my downvote. (more) |
— | 3 months ago |
| Comment | Post #290863 |
Second problem. Your question has to be self-contained. You are referencing another article, and it's lengthy [as much as I like reading Olin's material]. Add a summary, or quote the parts pertinent to your question. Besides, the referenced resource is on another forum. (more) |
— | 3 months ago |
| Comment | Post #290863 |
First problem schematic is missing. Purpose of the circuit or principles of the operation could have compensated somewhat for the lack of schematic, but those are missing too. (more) |
— | 3 months ago |
| Comment | Post #290774 |
Monica, your initial hunch that this is a Power User question was right. This is a troubleshooting question in the deep end of Power User. I didn’t bring it up sooner because we're running low on questions at EE.codidact. (more) |
— | 3 months ago |
| Comment | Post #290774 |
What’s the model of your UPS? If it has a diagnostic output (USB, or serial), then maybe we can glean what it’s thinking. (more) |
— | 3 months ago |
| Comment | Post #290774 |
Like Olin wrote in his answer, I wouldn’t expect the 5 year old battery in a UPS to be bad, assuming that the UPS runs on battery rarely. But if there was a mains outage every few weeks (or a faulty UPS thought that there was one) for 5 years, then the battery may have worn out. Deep cycle lead-aci... (more) |
— | 3 months ago |
| Comment | Post #290601 |
@#53832 The contact resistance will dwarf the bulk resistance of the pogo pin. Why are you concerned about the pogo pin resistance in the first place? What are you going to use the pogo pin for? (more) |
— | 4 months ago |
| Comment | Post #288954 |
Did DuckDuckGo approve it? I tried the `!codd` bang DuckDuckGo, but no bangs came up. There's always `site:electrical.codidact.com`, of course. (more) |
— | 4 months ago |
| Comment | Post #290541 |
@#36396 About availability. I needed an ADuM2250 in 2022. They were out of stock in regular channels for a regular price around 10 USD, and scalpers were asking 200 USD per chip. They are available on regular distributors at the time of writing. (Other IC manufacturers have pin-compatible parts ... (more) |
— | 4 months ago |
| Comment | Post #290541 |
@#36396 A convenient thing about Analog’s magnetic isolators is that some of them are tailored to standard digital buses. [These ones](https://www.analog.com/en/parametricsearch/11034#/) have a CAN transceiver and an isolator in the same package. CANH and CANL on one side, unidirectional TXD and RX... (more) |
— | 4 months ago |
| Comment | Post #290357 |
@#53469 Could you describe your entire system please, and the application? Where does the input come from? Where does the output go to? What are you trying to accomplish ultimately? (more) |
— | 5 months ago |
| Comment | Post #290324 |
*Jellybean* means industry standard design, multiple suppliers, typically low cost in its class. LTC7880 definitely isn't jellybean, TPS610333 probably isn't jellybean. (more) |
— | 5 months ago |
| Comment | Post #290284 |
Could the extended settling time be caused by the voltage coefficient in the ceramic capacitor? I'm guessing that your capacitor is X7R or some other Class 2 ceramic, because of its value in the uF range. Try a capacitor with the same Class 2 ceramic, but with a higher voltage rating, and see if th... (more) |
— | 5 months ago |
| Comment | Post #289856 |
My favorite writings about Lithium cell safety:
[Safety Concerns with Li-ion](http://batteryuniversity.com/learn/article/safety_concerns_with_li_ion), [Lithium Battery Failures](http://www.mpoweruk.com/lithium_failures.htm) . (more) |
— | 7 months ago |
| Comment | Post #289836 |
Which CAD package do you have in mind? I suspect that the best practices vary from one CAD package to another. In particular the best practice for the 2nd and 3rd questions would depend on whether or not the CAD has integrated libraries. (more) |
— | 7 months ago |
| Comment | Post #289483 |
Get an internship at a company. You'll get exposure to an industry-grade project in an industrial environment. (more) |
— | 9 months ago |
| Comment | Post #285993 |
Wilkins, what were the circumstances when your experienced friends shared their opinion about professional vs. hobbyist software? What kinds of boards or products are you and your friends designing? Were you all deciding what software to use for your next project? Were you asking them what softwar... (more) |
— | 9 months ago |
| Comment | Post #288720 |
[The meta reputation has been bugging me for a while.](https://meta.codidact.com/posts/278928) Thanks for taking care of this! (more) |
— | 9 months ago |
| Comment | Post #285817 |
[downvote comment] I don't agree that "ESD discharges are much slower (in the MHz range at the worst)". ESD discharges have frequency content that extends into 100s of MHz. The frequency content comes from the 1ns raise time at the front of the ESD discharge. This is mentioned in a lot of app not... (more) |
— | 10 months ago |
| Comment | Post #288641 |
@#52991 Hi Lorenzo, good to see you here. Answers can be biased by what TV is saying . I'm talking about layman TV news who sensationalize. I'm not talking about news in a trade journal. Elleanor was asking if questions about Boeing 737 MAX flaws are okay. The smoke had settled by now, so those... (more) |
— | 10 months ago |
| Comment | Post #288641 |
If approximately the same question were asked as "I need a joystick for a high reliability [medical, industrial, etc] application. Can I use a civilian game controller?" then it would be a real question. It would be an O.P.'s own application, and not something from TV news. The answer would be alo... (more) |
— | 11 months ago |
| Comment | Post #288641 |
@#36396 This is not a great question, because its origin lies in the mainstream lay media. They wanted to sensationalize [scandalize]. They picked the only item of hardware which they recognized. Ultimately, they were barking up a wrong tree. (more) |
— | 11 months ago |
| Comment | Post #288506 |
@#56656 Cable assembly shops are another place where you could ask about crimping tools. But it may turn out that the tools are too expensive for small production runs, and it makes sense to farm out cable modification to the cable assembly shop. (more) |
— | 11 months ago |
| Comment | Post #288010 |
(1) Not having decoupling capacitors is an error. (2) The battery powered circuit with wireless communication is an analysis of patient isolation. It sounds reasonable. (3) Only 2-lead ECG is AC-coupled. 3-lead id DC coupled. DC offset is removed from electrolytic effect will be present on both ... (more) |
— | about 1 year ago |
| Comment | Post #288010 |
Carl, I have several questions about the circuit design. Where are the power supply decoupling capacitors for the ICs? What's your analysis for patient isolation? This looks like a 3-lead ECG; why are you AC-coupling the Right Arm and the Left arm? (more) |
— | about 1 year ago |
| Comment | Post #287645 |
Raise times can be measured with an oscilloscope at the output pin of the device which is driving the line. (more) |
— | over 1 year ago |
| Comment | Post #287645 |
Let's check if transmission line effects in you SPI bus are appreciable. What's the raise time of the SPI digital signals? What's the mechanical length of the SPI bus? (more) |
— | over 1 year ago |
| Comment | Post #287480 |
What type of high frequency signal have you got (frequency range differential or single-ended)? What kind of cable and connector have you got? Which EMC standard do you need to comply with (e.g. CISPR 11 class B) ? (more) |
— | over 1 year ago |
| Comment | Post #287257 |
You've mentioned 1kW output. Is it going to be high current (say 30V, 33A) or high voltage (say 500V, 2A) ? (more) |
— | over 1 year ago |
| Comment | Post #287257 |
Andy, the input to the buck-boost is between the Vin+ and Vin-. I'm guessing that the load [a 3-phase motor?] will be between Vout and GND. Is the output always above GND? Or Can it be below GND too? (more) |
— | over 1 year ago |
| Comment | Post #278601 |
Another video on schematic clarity: [How to build a hierarchical structure for high-speed projects](https://www.youtube.com/watch?v=RGlRsl8vy6k) by Altium. (more) |
— | over 1 year ago |
| Comment | Post #279884 |
Comment for the O.P. Why is _winter day_ significant in this story? Because heating during the winter reduces air humidity. ESD is more likely in dry air. (more) |
— | over 1 year ago |
| Comment | Post #286766 |
Altium has got closer to Eagle with its current library architecture. This is a recent development. Altium started with a different library architecture [which was less sophisticated, in my opinion], and it still supports its historical architecture. (more) |
— | over 1 year ago |
| Comment | Post #286838 |
On the other end of the spectrum, we’ve got software developers, who learned how to program the systems with limited resources and real-time requirements. They peer into the system through software development tools. When a software issue raises hardware questions, they tend to seek help of an electr... (more) |
— | almost 2 years ago |
| Comment | Post #286838 |
On one end of the spectrum, we’ve got electrical engineers who learned to write quality code. They tend to debug with an oscilloscope, and sometimes program with a soldering iron. They keep these tools on their desks. Their strengths are in their ability to add firmware perspective to hardware requir... (more) |
— | almost 2 years ago |
| Comment | Post #286838 |
[I'm posting this as comments, because I don't think this is an answer to your question. It's not about programming skills.] In my observation, there is a spectrum of engineers who do embedded systems design and development. (more) |
— | almost 2 years ago |
| Comment | Post #286435 |
Exposed body connection is needed when you want a single MOSFET to switch current in both directions. If the body is connected to source, then the MOSFET can switch current only in one direction, because the body diode will always conduct in another direction. When the body terminal is exposed, you... (more) |
— | almost 2 years ago |
| Comment | Post #286030 |
The mention of "O-ring" a technical writer error [the TW wasn't technical enough], or an auto-correction artifact. It should have been "OR-ing", or "ORing". An [O-ring](https://en.wikipedia.org/wiki/O-ring) is a type of seal. (more) |
— | about 2 years ago |
| Comment | Post #286035 |
Maybe I'm missing something about your device. Is your product a PCBA by itself? Or, does it come in an enclosure? U.FL on the board, and some bigger connector (SMA, or BNC, or some other kind) on the enclosure. Is the enclosure metal or plastic? Is it grounded to chassis? (more) |
— | about 2 years ago |
| Comment | Post #286007 |
Post a sketch of the PCB floor plan which you have in mind. In case you have already (prematurely?) done the layout, post pictures(s) of your layout. (more) |
— | about 2 years ago |
| Comment | Post #285721 |
Are you going for the formal IEC 61000−4−2 certification test? Sometimes passing a test it a harder design problem than protection from the ESD in the field. That was my experience this December. (more) |
— | over 2 years ago |
| Comment | Post #285648 |
I've read about industry initiatives (on the level of IPC) to create standardized file formats. I don't know how much of it actually got defined and adopted. Trawl through [Printed Circuit Design & Fab magazine (free-of-charge industry rag)](https://www.pcdandf.com/pcdesign/). Maybe there are over... (more) |
— | over 2 years ago |
| Comment | Post #283693 |
This thermal relief has one fat spoke, because the PCB layout author first connected the pin with a fat trace, then pulled the GND copper pour over it. Sometimes I see thermal reliefs with 5 spokes (say at 0, 45, 90, 180, 270). (more) |
— | over 2 years ago |
| Comment | Post #283655 |
Frank, could you please add a link to the text where you saw these terms? Otherwise, if would be too risky for us to guess wrong. (more) |
— | over 2 years ago |
| Comment | Post #283239 |
Another example of a technical translation question on StackExchange: [Looking for translation of “закладная втулка” (threaded bushing?)](https://engineering.stackexchange.com/questions/24030/looking-for-translation-of-%D0%B7%D0%B0%D0%BA%D0%BB%D0%B0%D0%B4%D0%BD%D0%B0%D1%8F-%D0%B2%D1%82%D1%83%D0%BB%D0... (more) |
— | over 2 years ago |