Activity for Elleanor Lopez
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #292898 | Initial revision | — | 24 days ago |
| Question | — |
OPA2211 datasheet discrepancy Looking at Texas Instruments opamp OPA2211it mentions GBW of 80MHz at a gain of 100, and 45MHz at gain of 1: screenshot of the 1st page of a datasheet Looking at the bandwidth graph from Figure 10 in datasheet: chart It looks like 80MHz is unity gain bandwidth, and at a gain of 100 the band... (more) |
— | 24 days ago |
| Edit | Post #292688 | Initial revision | — | about 2 months ago |
| Question | — |
Why did the battery blow out? I have a bed for which the headrest can be adjusted. There are 2 separate power inputs for each side like in the picture: Imagealttext In addition, there is a set of 9V batteries on each side, presumably for backup: Imagealttext Yesterday I heard a loud bang and found one battery on the f... (more) |
— | about 2 months ago |
| Edit | Post #292525 |
Post edited: Excluded UL796 |
— | 2 months ago |
| Edit | Post #292525 | Initial revision | — | 2 months ago |
| Question | — |
Connector rated voltage vs IPC-2221B and IEC 62368 Rosenberger 23C25D-40ML5 specifies 500V RMS rating: Imagealttext Imagealttext Looking at the recommended landing pattern you can see that the distance between the signal landing pad and housing of the connector is 0.3025mm. IPC-2221B specifies minimum conductor spacing of 0.8mm for externa... (more) |
— | 2 months ago |
| Comment | Post #291741 |
I need to use these for high DC voltage bias in a very restricted space that also has to have noise immunity. Purely by regulation, if the connector is UL listed, is it allowed to use it out of specs if we verify that functionally it is a non-issue, or does that no longer comply with UL? (more) |
— | 5 months ago |
| Comment | Post #291734 |
Hi Lundin, thanks for the thought. I think some connectors do specify VRMS, for example MMCX series from TE. Also RF connectors, 170VRMS @sea level. (more) |
— | 5 months ago |
| Edit | Post #291734 | Initial revision | — | 5 months ago |
| Question | — |
Missing voltage rating I am looking at this RF connector. I see that insulation resistance and breakdown voltage are specified, but no voltage rating: Imagealttext I have two questions, one functional and one safety. Functionally, what is the maximum DC voltage I can bias this connector at (There is no voltage ratin... (more) |
— | 5 months ago |
| Edit | Post #291670 |
Post edited: |
— | 6 months ago |
| Comment | Post #291670 |
IEC 60417 ground symbols: No. 5019 Protective earth (ground): To identify any terminal which is intended for connection to an external conductor for protection against electrical shock in case of a fault, or the terminal of a protective earth (ground) electrode. (more) |
— | 6 months ago |
| Edit | Post #291670 | Initial revision | — | 6 months ago |
| Question | — |
ESD Table Earth Bonding Points - Why? We have ESD tables in the laboratory with Earth Bonding Points: Imagealttext These are directly connected to PE (I measured). It is my understanding that equipment has to be connected to PE directly and ESD mats and bracelets have to be connected to PE through high impedance for both safety and co... (more) |
— | 6 months ago |
| Comment | Post #291411 |
Hi Andy,
It was my understanding that if your source and line are matched and only the end of the line is terminated incorrectly, you get a single reflection that is dissipated in the source impedance. Only if both ends of the line are mismatched there are multiple reflections that die down after ... (more) |
— | 7 months ago |
| Edit | Post #291409 | Initial revision | — | 7 months ago |
| Question | — |
Understanding inductive ringing For my own understanding I tried modelling switching off an inductive load without a freewheeling diode to observe ringing. This is the model I used: Imagealttext 1.) Are the two main components of the resonant circuit L1 and Cwindings, where Cwindings is the inherent capacitance between the ... (more) |
— | 7 months ago |
| Comment | Post #291093 |
Fair enough, it would be interesting to know what the gradient looks like for such case. I suspect that standing near 750kV you would need to place your feet incredibly precise to not create a large enough voltage to kill you between your feet. Maybe the circuit was broken in less than a 1/4 phase an... (more) |
— | 8 months ago |
| Edit | Post #291092 | Initial revision | — | 8 months ago |
| Question | — |
Step voltage 750kV lines Some gentlemen decided to throw a hook with wire over 750kV lines in Belarus. They survived, however, I find in interesting to find out why. Assuming the connection to Earth was solid, there would be a large fault current and a gradient with step voltage: Imagealttext According to Mike Holt in... (more) |
— | 8 months ago |
| Comment | Post #276138 |
I believe the only circuit I have seen where LED had no series resistance added was with a flat cell battery, which in itself has a high output impedance, and therefore the LED gets to live another day. (more) |
— | about 1 year ago |
| Comment | Post #289574 |
Additionally, disassembling will void any kind of warranty. I mean, the cables are cut now, so warranty is off the table anyway. Personally I would guess it is a defective unit, I would buy exactly the same unit, hook it up to a PC the way it is intended to be used, observe if the ''spark'' is presen... (more) |
— | about 1 year ago |
| Comment | Post #289577 |
In what software did you draw these schematics? (more) |
— | about 1 year ago |
| Comment | Post #289348 |
@#52991 Is there some way you can edit these tags without turning the EE forum upside down? Each tag edit floats old questions to the top of the feed. (more) |
— | over 1 year ago |
| Comment | Post #287197 |
@#36396 Are you planning on finishing this? (more) |
— | over 1 year ago |
| Comment | Post #288784 |
I have to say something about the 'ordinary' board part. I took a guess at what the MCU he uses might be: K64P142M120SF5 for example. Port rise time can be 4ns. The majority of energy content is in frequencies up to 0.5x t_rise, therefore the frequency of concern is from the clock of 120MHz up to 500... (more) |
— | over 1 year ago |
| Edit | Post #288770 |
Post edited: |
— | over 1 year ago |
| Edit | Post #288770 |
Post edited: |
— | over 1 year ago |
| Edit | Post #288770 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Ground pour on outer layers on 4-layer PCB You have mentioned a few points yourself, so I will try to comment on those points and perhaps suggest some reasons to add or not to add a ground plane. You mentioned twisting (I suppose warping) of the board. I believe there is a chance this happens if the board is not symmetrical copper wise, so... (more) |
— | over 1 year ago |
| Comment | Post #288757 |
Thanks for the answer!
I am not taking a class, I am mostly busy with PCB design, but in the process I quite often find that I have a 'Why am I doing this in this particular way?'. So for example, application notes often specify to use 10uF in parallel with 1uF and to finish off 100nF. But when I ... (more) |
— | over 1 year ago |
| Edit | Post #288751 |
Post edited: |
— | over 1 year ago |
| Edit | Post #288751 |
Post edited: |
— | over 1 year ago |
| Edit | Post #288751 | Initial revision | — | over 1 year ago |
| Question | — |
How to convert dv/dt of noise into frequency for filter capacitor selection? Noise can be coupled between signal lines through parasitic capacitance formed between these signal lines, as $i = C\frac{dv}{dt}$ where C is the capacitance between the signal lines. Another way of noise coupling into signal lines is through inductive coupling, where changing magnetic fi... (more) |
— | over 1 year ago |
| Comment | Post #288641 |
So by the same logic something like electrical issues and system design with Maneuvering Characteristics Augmentation System that brought down Boeing737 MAX planes also cannot be discussed because it was covered by the media? I think the answers highlight the weak points in design choices and provide... (more) |
— | over 1 year ago |
| Edit | Post #288641 |
Post edited: |
— | over 1 year ago |
| Edit | Post #288641 | Initial revision | — | over 1 year ago |
| Question | — |
Titanic submarine control considerations The submarine built by OceanGate went missing on 18th June 2023. A lot of online criticism was directed towards the control hardware of the submarine - Logitech F710 controller. Imagealttext Imagealttext However, why is this the case? It has 2 dual axis potentiometers and some capacitive sensing... (more) |
— | over 1 year ago |
| Edit | Post #288550 | Initial revision | — | over 1 year ago |
| Question | — |
Cable voltage rating I was looking for guidelines of how to select appropriate cables for applications (I am interested in DC), I found IEC 183 standard which talks about high voltage cable selection for AC. Also, the status of the document is shown as withdrawn, so I assume it is not applicable. I found another docum... (more) |
— | over 1 year ago |
| Edit | Post #288461 | Initial revision | — | over 1 year ago |
| Question | — |
micro-RF connector crimping options Do micro-RF connector mating crimp connectors are ever sold separately together with a crimp tool? For example thisImagealttext I have looked through a lot of pages, and can only find PCB connectors + cable assemblies sold. Are RF connectors manufacturer specific and they do not share the crimp to... (more) |
— | over 1 year ago |
| Edit | Post #286744 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Siglent1104 oscilloscope channels lagging It was a firmware issue. SDS1xx4X-E Firmware Revision History And Update Instructions The hardware delay between ADC acquisitions was not accounted for. I flashed the scope with new firmware and the delay is gone (more) |
— | over 2 years ago |
| Comment | Post #286724 |
I work in academy and this screams homework. (more) |
— | over 2 years ago |
| Edit | Post #286670 | Initial revision | — | over 2 years ago |
| Question | — |
Siglent1104 oscilloscope channels lagging First I noticed that clock begins before chipselect gets pulled low on SPI. After eliminating potential sources I started to suspect the scope. I connected all 4 channels to function generator at different frequencies and observed 25ns gap between channel pairs. The probes were all the same 100Mhz st... (more) |
— | over 2 years ago |
| Comment | Post #286538 |
@#36396 I added description on how to inspect the graph in post, and also added verbal description of the graphs in case the picture cannot be opened. It is a screenshot from a video, unfortunately I don't know how to enhance quality of that. There is also a link to the video with embedded timestamp,... (more) |
— | over 2 years ago |