Activity for Lundinâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #291238 |
Ok so maybe the inductor is just meant to be (part of) a filter. Then the IC could very well be a linear regulator or just a transistor. (more) |
— | 21 days ago |
| Comment | Post #291238 |
I'm guessing the connector. And since it is a hand-held device running on batteries, voltage out to power something? Or does it use rechargeable batteries and that's voltage in? (more) |
— | 22 days ago |
| Comment | Post #291239 |
"The component to the left of the inductor in second picture looks to be a diode. It only has two terminals. The stripe at one end probably marks the cathode."
Nope, tantalum caps, the stripe marks + since they have polarity. And they like to explode :) (more) |
— | 22 days ago |
| Comment | Post #291240 |
@#52935 I found some boost converters for 3.3V by the semi-obscure brand Torex that might fit the bill, but I couldn't find any matching documentation about part markings. There's lots of linear regulators with markings 331 but that doesn't explain the inductor. Unless it is double-sided mounting an ... (more) |
— | 22 days ago |
| Edit | Post #291240 |
Post edited: |
— | 22 days ago |
| Edit | Post #291240 | Initial revision | — | 22 days ago |
| Answer | — |
A: What are these mystery components (one of wire coil, another labeled "100-10L A9")? The black one is a tantalum capacitor. There are various weird ways to mark these (because typing out `100u` instead of `100-` would be too easy...). If I'm correct in this case, I believe: - `100` stands for 100uF - `10` for 10V. - `L` is tolerance +/-10%. - From the size of it it looks like... (more) |
— | 22 days ago |
| Comment | Post #291110 |
That shouldn't be a problem for a PCB sitting in an enclosure, given that the usual anti-ESD measures were implemented.
Electronics love dry places. The more obvious issue that dry tends to go hand in hand with warm, and that's where all manner of issues can pop up. (more) |
— | about 1 month ago |
| Comment | Post #291085 |
I have the transceivers failing during production and I doubt the cause is ESD. I suppose hot-plugging during testing could be a culprit, but then the type of connectors used means the ground is always there before voltages. (more) |
— | about 1 month ago |
| Edit | Post #291080 |
Post edited: |
— | about 1 month ago |
| Comment | Post #291082 |
I guess the TVS values were picked because we already have the same ones elsewhere on the BoM protecting 24V on/off and the like. That and taking a bit of the blow in case someone shorts the supply against data lines. We have already considered adding TVS suitable for RS-485, I noticed there are some... (more) |
— | about 1 month ago |
| Comment | Post #291082 |
Oops yes this is a typo. Since the design is propriety, I cannot share it as-is, so I just quickly redrew the relevant parts in an online schematic program. (more) |
— | about 1 month ago |
| Comment | Post #291080 |
@#53661 It can be hot-plugged, yeah, but I don't see it related to the failures. The PCB ground will be sitting close to the chassis ground potential - it will be grounded to chassis from where the PCB is connected, as well as at a few other places where shielded connectors are attached to the chassi... (more) |
— | about 1 month ago |
| Edit | Post #291080 | Initial revision | — | about 1 month ago |
| Question | — |
MAX485 transceivers breaking, Pi filter generating spikes? Problem description & speculation about causes I've having a problem with MAX485 transceivers breaking intermittently, passing our production tests but later failing. The error phenomenon is wrong signal voltage levels on the RS485 lines, as well as the transceiver failing to return the signals to... (more) |
— | about 1 month ago |
| Comment | Post #290874 |
The slightest scratch will mean that the solder mask is leaking however. Solder mask is literally what it says: a means for preventing solder to end up on top layer traces. Using it for anything else (including isolation) is questionable practice. Anyway, the standard practice for anything in tough e... (more) |
— | 2 months ago |
| Comment | Post #290874 |
How would the signals get to the SMD connector without vias? Some sort of blind vias? Are they waterproof and who says so? Anyway, to be honest this is such a bad idea from the start. Not just because of water, but because of salt, galvanization and probably a bunch of other problems too. Separate th... (more) |
— | 2 months ago |
| Comment | Post #290774 |
I still think this question would be more suitable for Power Users, where computer hardware questions are [explicitly on-topic](https://powerusers.codidact.com/help/faq), whereas here on EE the question is [explicitly off-topic](https://electrical.codidact.com/help/topics) since it is still about "hi... (more) |
— | 2 months ago |
| Comment | Post #290541 |
@#52935 Regarding availability I don't think you can look at the Covid component crisis, since pretty much every silicon vendor's logistics chains were broken. I couldn't get plain schottky diodes of any brand with less than 30 weeks... same deal with any Cortex M of pretty much any brand. ST and Inf... (more) |
— | 4 months ago |
| Comment | Post #290541 |
@#52935 I will use a modern standard transceiver like MCP2562FD which has great voltage tolerances and good ESD protection. Then TVS, common mode EMI filter etc etc on top. Not worried about protecting the actual bus, we've passed similar nasty EMC testing before when using RS485, but we didn't use g... (more) |
— | 4 months ago |
| Comment | Post #290541 |
Thanks for your reply! Though I'm not following your concerns about CAN. The isolator, no matter type, will have to be placed between the MCU and the transceiver ("CMOS levels"). The Tx and Rx signals there are not bidirectional. The isolator I linked and intend to use is 2 channel, so there's one ch... (more) |
— | 4 months ago |
| Comment | Post #290533 |
@#52987 Both primary and secondary will be supplied with old school LDOs and we'll also encapsulate the whole PCB with screens. Decoupling caps on all supply pins naturally. I don't think there's a risk that the supply traces etc pick up substantial currents from radiated EMI that way? Maybe it's wis... (more) |
— | 4 months ago |
| Edit | Post #290533 | Initial revision | — | 4 months ago |
| Question | — |
Most reliable galvanic isolation technology for extreme EMI environments? I'm working on another project with extreme EMC requirements as per various notorious military EMC standards. Civilian product but for military use, and as such subject to the toughest levels of conducted/radiated susceptibility, 200V/m fields across an 2MHz-18GHz range, peak pulses of far higher ene... (more) |
— | 4 months ago |
| Edit | Post #290532 |
Post edited: |
— | 4 months ago |
| Edit | Post #290532 | Initial revision | — | 4 months ago |
| Article | — |
How to introduce or port my microcontroller project to MISRA C? MISRA C has become a de facto standard for all embedded systems firmware, no matter if it is safety-related or not. C comes with a lot of freedom, which makes it powerful yet dangerous. MISRA C is a safe subset of the C language, acting as a filter to block poorly-defined or otherwise dangerous parts... (more) |
— | 4 months ago |
| Edit | Post #290434 |
Post edited: |
— | 4 months ago |
| Comment | Post #290423 |
Either solution sounds over-engineered IMO. If you have a CAN bus, you have a MCU, so why not use the MCU? (more) |
— | 4 months ago |
| Edit | Post #290434 | Initial revision | — | 4 months ago |
| Answer | — |
A: CAN BUS monitoring with a LED I've done similar things on UART lines, but for significantly lower baudrates (9600 etc) than traditionally used on most CAN buses. It's also easier to do when you have 5V guaranteed to be well-over the LED Vfwd, which the CAN lines do not necessarily live up to. For instance there are 3.3V suppl... (more) |
— | 4 months ago |
| Edit | Post #286121 |
Post edited: |
— | 5 months ago |
| Comment | Post #290231 |
Also this could mean anything. We have high voltage regulation (>1000VAC, >1500VDC) , we have "low" voltage regulation (50-1000VAC, ~75-1500VDC) and "extra low" voltage regulation (<50VAC, < ~75VDC). These categories can in turn be divided into many sub-categories: isolated regulators, transformers,... (more) |
— | 5 months ago |
| Edit | Post #286121 |
Post edited: |
— | 5 months ago |
| Edit | Post #286121 |
Post edited: Minor spelling and fortmatting |
— | 5 months ago |
| Edit | Post #289867 |
Post edited: |
— | 7 months ago |
| Edit | Post #289867 | Initial revision | — | 7 months ago |
| Answer | — |
A: Will shorting a lithium ion battery cause an explosion? It depends on how you define "battery". I guess the definition is different depending on if you are a chemist, an engineer or a consumer. When electrical engineers speak of batteries, they typically mean a battery cell - a component. Then there's the end user application with a cell + electronics emb... (more) |
— | 7 months ago |
| Comment | Post #286035 |
I think I've seen this app note before, I use the very Silabs parts that they use as example. But most of it is generic ESD and the figure 19 didn't really bring anything new other than "take care about the parasitics of the selected TVS diode", which was already mentioned in the question here. Figur... (more) |
— | 7 months ago |
| Comment | Post #289688 |
Which part is the Darlington, more specifically? One of the classic ULNs I take it? These are notoriously brittle and shouldn't be used in industrial applications. Consider some "smart" MOSFET driver instead, with plenty of built-in protection. (more) |
— | 7 months ago |
| Edit | Post #289623 |
Post edited: |
— | 8 months ago |
| Edit | Post #289623 | Initial revision | — | 8 months ago |
| Answer | — |
A: What residential wiring questions are on-topic here? The reason I left that comment is because determining the quality of a coaxial cable involves electrical engineering more so than an electrician, let alone some DIY. The rule of thumb "would you ask this to an engineer or electrician" is good. However, in this case you are unlikely to get a good ... (more) |
— | 8 months ago |
| Comment | Post #289574 |
And well, trouble-shooting PSUs on the product level is probably off-topic here. We'd expect questions to rather be about how to trouble-shoot them on the component level. Rectifier bridges, transformers, regulators, isolation, filters etc etc. (more) |
— | 8 months ago |
| Comment | Post #289574 |
You won't ever get to the bottom of the cause of the "spark noise" unless you dissect the PSU, do some light reverse-engineering and see what may be the cause. However, please note that disassembling these can be dangerous even with power disconnected since the internal caps can hold high loads for q... (more) |
— | 8 months ago |
| Edit | Post #289515 | Initial revision | — | 8 months ago |
| Answer | — |
A: Professional vs Hobbyist advice and potentially dangerous projects The main problem with a question along the lines of "how do you design a product for medical applications" is that it's way too broad. You cannot reasonably write a somewhat complete answer because it would be a very long one. The general approach of all these Q&A sites is that in case an answer ... (more) |
— | 8 months ago |
| Comment | Post #289423 |
I deliberately picked PID because it has only one sensible definition in the context of Electrical Engineering. Process ID is (arguably) not a term used in EE, so therefore the term which _is_ used, established and well-known too, should be the one that get the tag as well as the abbreviation. Otherw... (more) |
— | 8 months ago |
| Edit | Post #289416 |
Post edited: |
— | 8 months ago |
| Comment | Post #289348 |
@#52991 Ok so I tried to compile a draft for some sort of general policy here: [Tag creation/deletion crieria](https://electrical.codidact.com/posts/289416). And yeah this might mean that tags such as `voltage` are free to delete. Any feedback is appreciated. (more) |
— | 8 months ago |