Activity for Lundin
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #295313 |
Post edited: |
— | 8 months ago |
| Edit | Post #295313 |
Post edited: |
— | 8 months ago |
| Edit | Post #295313 | Initial revision | — | 8 months ago |
| Answer | — |
A: Need clarification on SWDIO/SWCLK length‑matching and “shielding” for STM32WBA5MMG debug connector This is senseless. They state these things because they expect you to run SWD at extreme speeds. While some flavours of SWD may allow up to 50MHz something, there is no reason why you would ever want to run it that fast. There isn't nearly enough data present in the MCU that needs to be transf... (more) |
— | 8 months ago |
| Comment | Post #295269 |
@#117260 Spontaneously it seems a bit far-fetched, since it is really quite a technical niche question. (more) |
— | 8 months ago |
| Comment | Post #295265 |
@#64549 If properly implemented the /CS (aka /SS) signal is the only one who must have a pull up, but in general it isn't a good idea to let digital signals "float" when not driven actively. In this case it seems that the signals go to a connector, which may perhaps get disconnected? Otherwise, e... (more) |
— | 8 months ago |
| Edit | Post #295269 |
Post edited: |
— | 8 months ago |
| Edit | Post #295269 | Initial revision | — | 8 months ago |
| Answer | — |
A: Clarification on shopping questions As it stands, that would probably be off-topic here, even if the question comes with a very detailed specification. And even though picking one is quite qualified work that requires an experienced engineer. At some point I meant to write a microcontroller selection Q&A but never got around to ... (more) |
— | 8 months ago |
| Comment | Post #295265 |
SPI idles high so that seems to be perfectly reasonable feedback, particularly the /CS pin. So why not just do that, what do you need our feedback for as well? A bunch of resistors add no cost especially since you already got a 10k reel in the BoM. As for 4k7 vs 10k that's pedantic, it won't matt... (more) |
— | 8 months ago |
| Comment | Post #295180 |
What's the frequency of the ripple? If it is the same as the switch regulator's frequency, then that is a problem not easily solved. So for sensitive analog/RF stuff maybe consider the classic design of first having a buck(/boost) regulator followed by a linear regulator. It does solve a whole lo... (more) |
— | 9 months ago |
| Comment | Post #295134 |
I've done similar designs - roughly where a low RDS(on) N channel power MOSFET was used to distribute all power, including the supply of a MCU. It had a pull-down on the gate, but could be activated from numerous sources: from a manual switch, from MCU GPIO or from a voltage supervisor. So 3 diff... (more) |
— | 9 months ago |
| Edit | Post #295131 | Initial revision | — | 9 months ago |
| Answer | — |
A: CAN termination jumper (120 Ω → 60 Ω) > Is this a correct way to implement selectable 120 Ω / 60 Ω CAN termination using a jumper? It is weird to place both terminators on the same board. While this might fix the problem of having an ideal 60Ω between CANH and CANL, it also means that there can be to protection against reflections... (more) |
— | 9 months ago |
| Comment | Post #294204 |
@#8114 I just assumed it would be, but I suppose this might be different in various parts of the world and maybe between different brands etc. (more) |
— | 10 months ago |
| Edit | Post #291971 |
Post edited: Typos and clarifications |
— | 10 months ago |
| Comment | Post #294912 |
Why is there an optocoupler there since you use same ground on primary and secondary? As designed, it just acts as dysfunctional, slow, non-isolated BJT. Regarding the reverse polarity protection you need to ensure that GND is only coming from one single place like a connector, or otherwise the c... (more) |
— | 11 months ago |
| Comment | Post #294797 |
@#116119 I just realized that depending on what ADC you got the 10k series resistor may or may not work. I'm used at SA ADC with built-in caps but I guess that's not necessarily always the case - see https://electronics.stackexchange.com/questions/757507/is-it-common-practice-to-add-a-capacitor-t... (more) |
— | 11 months ago |
| Edit | Post #294797 | Initial revision | — | 11 months ago |
| Answer | — |
A: Need guidance: Sensing 12 V and protecting hall sensor input The BJT is overkill and might have issues of its own (voltage spec, ESD etc) and you don't need to switch a lot of current either. Also a plain zener is too slow to help against spikes, you need a TVS. Similarly with the optocoupler, it is overkill and in general just a last resort in case you... (more) |
— | 11 months ago |
| Edit | Post #294784 |
Post edited: |
— | 11 months ago |
| Edit | Post #294784 | Initial revision | — | 11 months ago |
| Answer | — |
A: Methods to propagate error codes in C firmware > Functions return error codes. If a function needs to pass a result to the calling code, it does it through an output parameter This is the proper way. Static analyzers and compilers often check to ensure that the result of a function is used, so the caller won't be able to ignore it by accid... (more) |
— | 11 months ago |
| Edit | Post #294698 |
Post edited: |
— | 11 months ago |
| Comment | Post #294698 |
@#116119 You can use SPST indeed since you only need to hook the terminating resistor to one of CANH and CANL and it does no harm there if the other end of it is left floating. The part you suggested has too crappy ESD ratings to sit on a typical CAN bus but maybe that's not important? For indust... (more) |
— | 11 months ago |
| Edit | Post #294698 |
Post edited: |
— | 11 months ago |
| Edit | Post #294698 |
Post edited: |
— | 11 months ago |
| Edit | Post #294698 | Initial revision | — | 11 months ago |
| Answer | — |
A: Dealing with multiple CAN terminations in a master-slave-BMS setup Your bus length is so short that you can consider the battery connection a stub. As long as there is 60Ω between CANH and CANL and the cable to the battery is not ridiculously long (many meters), it will work just fine. If you add a third termination you end up with (1/120 + 1/120 + 1/120 = 1... (more) |
— | 11 months ago |
| Comment | Post #294620 |
@#52935 But why, if instead you could just let the P MOSFET cut the power. (more) |
— | 12 months ago |
| Comment | Post #294620 |
@#52935 But for that to happen 3A must run through it, which is the problem I'm pointing out. Even if it is just a short current burst it might be enough to melt wires etc. (more) |
— | 12 months ago |
| Edit | Post #294620 | Initial revision | — | 12 months ago |
| Answer | — |
A: Buck converter protection and enable/Disable circuit Some general remarks: - The reverse polarity protection won't work since D7 SMDJ58A is a unidirectional TVS. Upon reverse polarity, this TVS will start to conduct before the MOSFET switches off. You should use a bidirectional TVS for this to work as intended and prevent a current rush. - An... (more) |
— | 12 months ago |
| Edit | Post #294373 | Initial revision | — | about 1 year ago |
| Answer | — |
A: Robust digital output protection Generally you can protect against most kind of harmful events with a TVS placed on the output, with a value slightly higher than your expected signal voltage so roughly 6V. The only thing the idea of building this yourself with BJTs got going for is somewhat fast switching but <100Hz is slow. ... (more) |
— | about 1 year ago |
| Comment | Post #294200 |
This site is about electronics design. So whenever asking a repair question, make sure to include sufficient details about the circuit and your troubleshooting steps so far, what you have measured etc. Questions about repair of consumer products are likely more suitable for the proposed new site ... (more) |
— | about 1 year ago |
| Edit | Post #294204 | Initial revision | — | about 1 year ago |
| Answer | — |
A: safe to pour isopropyl alcohol over toothbrush gear, circuit, and coil? The main issue is just if it's battery powered or not. In case it is, always remove the battery first. Before any electronic device is cleaned or otherwise tampered with, one must always remove the power. Apart from that, isopropyl is the best way to clean electronics, in terms of cleaning and... (more) |
— | about 1 year ago |
| Edit | Post #294006 |
Post edited: |
— | over 1 year ago |
| Edit | Post #294006 |
Post edited: |
— | over 1 year ago |
| Edit | Post #289284 |
Post edited: |
— | over 1 year ago |
| Comment | Post #294006 |
Not that I actually want moderator privileges... But it feels like tag editing should be possibly by trusted users. We had another user [here](https://electrical.codidact.com/posts/289342) who did a great job cleaning up and renaming tags who should have similarly gotten trusted with tag deletion... (more) |
— | over 1 year ago |
| Comment | Post #294006 |
@#8046 I can't find a way to rename or delete tags so I guess "edit tags" isn't a sufficient privilege. I can create synonyms and set parent tags though. (more) |
— | over 1 year ago |
| Comment | Post #294006 |
@#36396 Okay if you say so :) Anyway I'll let this post sit here for a week or two before I do anything, in case someone got feedback. (more) |
— | over 1 year ago |
| Edit | Post #294006 | Initial revision | — | over 1 year ago |
| Question | — |
Proposed clean-up of bad tags I propose that we get rid of a lot of bad tags that should never have been created. I went through them all and this is what I think we should get rid of or rename. I'll leave this meta post here for a week or so for feedback, before I go ahead and edit out tags that nobody got any objections ... (more) |
— | over 1 year ago |
| Edit | Post #293968 |
Post edited: |
— | over 1 year ago |
| Comment | Post #293898 |
Coin cell batteries have pretty high ESR to begin with (much higher than the MOSFET Rds(on)) so I don't think they are even capable of creating a big inrush current when charging up the caps? (more) |
— | over 1 year ago |
| Comment | Post #293896 |
This kind of thing seems more suited for chat. Unfortunately Codidact has no on-site chat (and it isn't likely a priority to implement), but the [EE chat](https://chat.stackexchange.com/rooms/15/electrical-engineering) over at Stack Exchange is pretty active. (more) |
— | over 1 year ago |
| Comment | Post #293878 |
HDMI is digital but the 3.5mm audio jacks are analog so yeah those might pick up EMI. You could experiment by replacing that cable with a shielded one grounded to PC chassis, or use one with some randomly picked ferrite. (more) |
— | over 1 year ago |