Activity for Nick Alexeev
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #289344 | Initial revision | — | 9 months ago |
| Answer | — |
A: Correct way to think about thermal noise? > If a data sheet gives the thermal noise (of +3/-3 standard deviations) as 1 uVpp does it mean that out of every thousand samples, 3 will have noise more than ±1 uV at any sample rate? 1000 sps will lead to 3 samples having more than ±1uV noise in a second, 2000 sps will lead to 6 samples having mo... (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 |
| Edit | Post #287302 | Question closed | — | 9 months ago |
| Edit | Post #288922 |
Post edited: |
— | 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 |
| Edit | Post #288119 | Initial revision | — | 12 months ago |
| Answer | — |
A: MOSFET protection with TVS: at the source pin or at the drain pin If you put the Fat load-dump TVS downstream of the reverse-polarity protection MOSFET [^1], then the load dump current would have to flow through the MOSFET. The MOSFET would have to be rated for that current. If you put the Fat load-dump TVS upstream of the reverse-polarity protection MOSFET, th... (more) |
— | 12 months ago |
| Edit | Post #288075 | Initial revision | — | about 1 year ago |
| Answer | — |
A: How can I fix this 4-20 mA current loop to source current that matches current sink on its input? I'd rather use the AD4111 as a high-side current sensor, instead of creating an "inverter" which would generate an equal and opposite current. Each current input of the AD4111 (IINx+ and IINx-) is essentially a differential voltage input with a built-in 50 Ω resistor between them. It can work as ... (more) |
— | about 1 year 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 |
| Edit | Post #278602 |
Post edited: |
— | over 1 year ago |
| Edit | Post #287332 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Is ESD overhyped? ESD precautions can save a lot of tedious failure analysis. A very inconvenient thing about ESD is that a failure can be attributed to ESD only by ruling out every other possible cause. ESD failure is established by exclusion. One checks every other possible failure hypothesis, and none of them ... (more) |
— | over 1 year ago |
| Edit | Post #287330 |
Post edited: |
— | over 1 year ago |
| Edit | Post #287330 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Low-pass filter after the output DAC in CD players [In addition to what Olin wrote earlier.] I looked-up one of the references from the textbook, and I may have found the answer which the author had in mind. > This entire spectrum must not be passed on to the player amplifier and loudspeaker. Even though the frequencies above 20 kHz are inau... (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 |
| Edit | Post #287203 |
Post edited: |
— | over 1 year ago |
| Edit | Post #287203 | Initial revision | — | over 1 year ago |
| Question | — |
Low-pass filter after the output DAC in CD players [Disclaimer. This is not for an academic class. I'm self-studying.] I’m reading an introductory book on DSP for audio and computer music [Steiglitz 1996, ISBN 0-8053-1684-1 p. 287]. One of the sections discusses oversampled D/A conversion at the output of the CD players. The audio stream is ... (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 |
| Edit | Post #286766 | Initial revision | — | almost 2 years ago |
| Question | — |
Altium. Reusing schematic symbols for pin-compatible parts. I want to create a schematic symbol and reuse it for multiple ICs which have identical pinouts. For example, OpaMPS, or the venerable SN74LS00, SN74HC00, SN74HCT00. How can I do this in an Altium library without copying and pasting the symbol every time? I'd like to create a library where I don'... (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 |
| Edit | Post #286035 | Initial revision | — | about 2 years ago |
| Answer | — |
A: How to protect RF switches from ESD? > In this case the antenna connector is the standard horrible little U.FL, which is connected with coaxial to a bigger one grounded to chassis. The main ESD risk is when someone is connecting or removing the coax. It's quite easy to touch the center pin with ones fingers on a U.FL. from [this commen... (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 |
| Edit | Post #285155 | Question closed | — | over 2 years ago |
| Edit | Post #280125 |
Post edited: |
— | over 2 years ago |
| Edit | Post #283679 |
Post edited: |
— | over 2 years ago |
| Edit | Post #283679 |
Post edited: |
— | over 2 years ago |
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