Activity for Lundinâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #292698 |
I don't know this bus but surely stubs and termination must be a major consideration as well. A stub of just a few decimeters might have a big impact at speeds like this, causing signal reflection. (more) |
— | about 2 months ago |
| Comment | Post #292688 |
Was there any printing on the batteries that gave hints about the chemistry? Maybe they weren't regular alkaline, maybe NiMH or NiCd although those are relatively safe too. Lithium chemistries are more likely to get a thermal escalation and go out with a bang in case of a short (caused by dust etc) o... (more) |
— | about 2 months ago |
| Edit | Post #292375 |
Post edited: |
— | 3 months ago |
| Edit | Post #292375 |
Post edited: |
— | 3 months ago |
| Edit | Post #292375 | Initial revision | — | 3 months ago |
| Answer | — |
A: What is connector pitch and how to measure it? Pitch is defined as the center-to-center measurement between two pins/legs of the component. Connectors in particular are always categorized by manufacturers/retailers based on pitch, so it is the single-most important property to learn about when trying to identify or specify a connector. A ... (more) |
— | 3 months ago |
| Edit | Post #292374 | Initial revision | — | 3 months ago |
| Question | — |
What is connector pitch and how to measure it? When posting identification or general questions related to connectors, integrated circuits or other parts with pins/legs, engineers always speak about something called pitch. What is the meaning of the term and how can I tell what pitch my connector has? (more) |
— | 3 months ago |
| Edit | Post #292247 |
Post edited: |
— | 3 months ago |
| Edit | Post #292247 | Initial revision | — | 3 months ago |
| Answer | — |
A: Do hobbyist slabtop Wi-Fi modifications need to consult FCC regulations? During FCC (or any other EMC) testing, the manufacturer will use some antenna(s) and only those antennas will be the ones approved. If you modify the antenna or use one which wasn't used in the test, then the item is no longer conforming. Similarly, if a product's housing serves as signal/chassis ... (more) |
— | 3 months ago |
| Comment | Post #292089 |
When a CAN controller fails to send, it automatically tries again. It will increase an error counter and after failing a number of times go "error passive", meaning it can no longer send error frames driving the bus to the dominant state. If the error counter keeps increasing it will eventually go "b... (more) |
— | 4 months ago |
| Comment | Post #291971 |
@#52935 Yeah there are lots of mode selection pins like that on diverse MCUs. They all work slightly different however, but perhaps I should add a note about checking special pins. (more) |
— | 4 months ago |
| Edit | Post #291987 |
Post edited: |
— | 4 months ago |
| Edit | Post #291987 | Initial revision | — | 4 months ago |
| Answer | — |
A: How to operate a chip very close to its absolute maximum voltage? The term absolute maximum ratings has a well-defined meaning in datasheets, meaning stress values that the part will endure for a short period of time without breaking. And the opposite: if you exceed asbolute maximum ratings, it may break. The absolute maximum ratings of this particular part coul... (more) |
— | 4 months ago |
| Edit | Post #291971 |
Post edited: |
— | 4 months ago |
| Comment | Post #291971 |
This is a bit of a work in progress still, but I'm posting it here regardless so that I might get some feedback. Something missing? General feedback & proof-reading is most welcome! (more) |
— | 4 months ago |
| Edit | Post #291971 | Initial revision | — | 4 months ago |
| Article | — |
Troubleshooting a microcontroller that has stopped responding When working with microcontrollers, one will sooner or later face the situation where the MCU is not responding. Either it's a new PCBA you are trying to get up and running, or something that previously worked then something happened and now you are stuck. The in-circuit debugger is typically giv... (more) |
— | 4 months ago |
| Edit | Post #291745 | Initial revision | — | 5 months ago |
| Question | — |
Internal server error 500 while searching for tags Searching for a tag name using a string that doesn't exist in any tag causes internal server error 500. Reproduce this way: - Click Tags in the menu - In the search box, type something that doesn't exist as a tag, for example `bananas`. - Click the magnifying glass search icon. - Internal serv... (more) |
— | 5 months ago |
| Comment | Post #291734 |
@#56656 I've only seen it in terms of no insulation break down voltage. Though this is admittedly far from my area of expertise - I just happen to use these connectors a lot :) I think you'll need a connector expert, so poking Wurth support is probably the way to go. (more) |
— | 5 months ago |
| Comment | Post #291734 |
I think I've seen 60VAC reappearing as some "de facto" rated voltage standard for these U.FL connectors no matter brand. These are based on the Hirose U.FL series, which inconveniently doesn't seem to specify a voltage rating either (other than 200VAC breakdown). If you want to be sure for your parti... (more) |
— | 5 months ago |
| Edit | Post #291385 |
Post edited: |
— | 6 months ago |
| 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) |
— | 8 months 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) |
— | 8 months 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) |
— | 8 months 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) |
— | 8 months ago |
| Edit | Post #291240 |
Post edited: |
— | 8 months ago |
| Edit | Post #291240 | Initial revision | — | 8 months 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) |
— | 8 months 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) |
— | 8 months 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) |
— | 8 months ago |
| Edit | Post #291080 |
Post edited: |
— | 8 months 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) |
— | 8 months 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) |
— | 8 months 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) |
— | 8 months ago |
| Edit | Post #291080 | Initial revision | — | 8 months 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) |
— | 8 months 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) |
— | 9 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) |
— | 9 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) |
— | 9 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) |
— | 10 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) |
— | 10 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) |
— | 10 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) |
— | 10 months ago |
| Edit | Post #290533 | Initial revision | — | 10 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) |
— | 10 months ago |
| Edit | Post #290532 |
Post edited: |
— | 10 months ago |