Activity for Lundin
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #285201 |
I believe it's the other way around: a series resistor is mandatory but the fuse is optional. From IEC 60079:11 9.1 "In level of protection "ic" safety barriers, the minim requirement is a single zener diode and a current limiting resistor". Where "ic" means intrinsic safety zone 2, the lowest requir... (more) |
— | over 2 years ago |
| Comment | Post #285171 |
I disagree, since the OSI model is fundamental to any data communication. For example I often find myself in discussions where people ask how to send data over CAN bus or UART. Then I have to explain that how to send data isn't covered by CAN or UART, since they only specify physical and data link la... (more) |
— | over 2 years ago |
| Comment | Post #285155 |
I started a discussion regarding if these kind of questions should be on-topic here or not, see https://electrical.codidact.com/posts/285166. (more) |
— | over 2 years ago |
| Comment | Post #285082 |
Curious definitions. In EU we have the "low voltage directive" which applies to everything >50VAC or >75VDC. It doesn't seem to be harmonized with the standard you mention. Generally I'd say that IEC/ISO standards are more canonical than EU directives, but this also seems like it would a source of co... (more) |
— | over 2 years ago |
| Comment | Post #284818 |
Most of the resistance will be in the actual wires and probes, especially so for cheap instruments that come with low quality probes. (more) |
— | over 2 years ago |
| Comment | Post #284636 |
Hmm, not really convinced... though I do have bad experience of Traco, they aren't nearly as 'premium' as they claim to be. At any rate, it sounds like a 33V TVS directly after the switch would be a good idea for spike immunity purposes. And if you are correct about the reason why the Traco blew, suc... (more) |
— | over 2 years ago |
| Comment | Post #284636 |
Is the heater really to be regarded as a resistor and not as a coil? I know very little of these and I suppose ceramic heaters are supposed to eliminate the need for a coil. But when you say that you blew the power supply and the MCU too, it sounds a lot like reverse EMF. Then the switch signal bounc... (more) |
— | over 2 years ago |
| Comment | Post #284624 |
How do you limit the current of the LEDs? Right know you are feeding them with as much as your power source can give. What makes you think it's the MOSFET that's blown? It is far more rugged than the LEDs, rated at several A, while the average LED is rated at 20mA. (more) |
— | over 2 years ago |
| Comment | Post #284542 |
I think safety-related applications is one of the difficult "grey areas" here. For example it's quite common on SE that some hobbyist wants to mod something on their car or bike by smacking on some Arduino that they found in a packet of corn flakes. Which is both dangerous as well as wildly illegal i... (more) |
— | over 2 years ago |
| Comment | Post #284215 |
The larger problem is site activity, there's barely anyone posting questions. A couple of users repeatedly asking diverse questions might just be what the site needs, no matter question quality. All of these questions were perfectly on-topic, mind you. So they are already far higher quality than DIY ... (more) |
— | over 2 years ago |
| Comment | Post #283906 |
Btw depending on what battery chemistry this is, then 9V fully charged might mean 10-11V. And down to somewhere around 7V when low. Obviously it isn't a good a idea to drive a LED directly from a raw battery voltage. (more) |
— | over 2 years ago |
| Comment | Post #283906 |
@#36396 Wouldn't the worst case be the minimum voltage drop, not the maximum? The part didn't list a minimum so I used the typical value. It's better that a LED shines ever so slightly dimmer than supplying it with too high current. Also as I'm sure you know, In practice every modern LED out there ca... (more) |
— | over 2 years ago |
| Comment | Post #283904 |
Peak forward current listed below absolute maximum ratings is the stress value they promise that the diode can take for a short while. If you feed it that continuously it will eventually burn to a crisp. _Don't_ design using absolute maximum ratings! You should be looking at electrical characteristic... (more) |
— | over 2 years ago |
| Comment | Post #283693 |
5 seems common and I've seen even more... which was also bad for soldering. (more) |
— | over 2 years ago |
| Comment | Post #283693 |
The missing hole is just me having forgotten to enable some layer in the CAD tool - I don't do any PCB layout myself. But the layout here was just plain weird and I couldn't make any sense of it. (more) |
— | over 2 years ago |
| Comment | Post #283244 |
Rather than drawing these by hand all the time, consider using a schematics editor. There's plenty of free ones out there, like https://www.digikey.com/en/resources/design-tools/schemeit. Or https://www.falstad.com/circuit/ which also serves as a simulator - you can run and troubleshoot digital logi... (more) |
— | almost 3 years ago |
| Comment | Post #283242 |
Thanks! This further proves how tricky it is to translate such things. "Cable canal" was my literal translation from Swedish, but I could already tell that it sounded weird. "Cable duct" was something I came up with after random Google searches. Cable tray I wouldn't even have considered. (more) |
— | almost 3 years ago |
| Comment | Post #283240 |
Yet another example: dump "solder flux" in Google translate and it gives me "lödflöde" in Swedish, meaning "solder flow" - which is nonsense. (more) |
— | almost 3 years ago |
| Comment | Post #283240 |
There's cases where I've hired a professional translator to translate some manual to English, but even them came back and asked about how to translate technical details, because in order to correctly translate specific technical terms, you need domain knowledge. Sure there are specialized technical d... (more) |
— | almost 3 years ago |
| Comment | Post #283240 |
As I wrote in the question "these terms are far too technical to find in a dictionary". The capacitor example was just a funny anecdote, a capacitor it's a well-known component and probably even taught in science classes in high school. But terms like the "cable tray" are highly specialized. Another ... (more) |
— | almost 3 years ago |
| Comment | Post #282746 |
Here on the Internet ALL CAPS is considered shouting here and therefore rude. You should stop doing that if you plan to keep using the Internet. (more) |
— | almost 3 years ago |
| Comment | Post #282729 |
Covering lamps with aluminium plate isn't Electrical Engineering. Kindly check what's on-topic at a site before you post. https://electrical.codidact.com/help/topics (more) |
— | almost 3 years ago |
| Comment | Post #282543 |
Ah yeah, that might actually be why I had a gut reaction to lower the resistance. Now I recall making that very error too on an old LM317, drawing too little current through the resistors, after which the output voltage went bad. (more) |
— | almost 3 years ago |
| Comment | Post #282543 |
For some LDOs this is the case, but I can't tell if it matters for this one. At any rate you'll want to avoid oddball resistor values in your BoM, for better availability and reduced price. (more) |
— | almost 3 years ago |
| Comment | Post #282543 |
I haven't used this particular part, but generally you'll want the adjust resistors to be fairly low. You can probably divide them by 5 to 10 something. Also, tinker around with the formula until you find two values that are close to standard series values. 500R and 4k7 for example would be fairly cl... (more) |
— | almost 3 years ago |
| Comment | Post #282152 |
You could also write self-answered Q&A which is perfectly fine too, encouraged even. Example: [Driving relay, transistor keeps failing](https://electrical.codidact.com/posts/276116). This are typically about one single, specific issue. And it can be targeted towards any knowledge level - you could wr... (more) |
— | almost 3 years ago |
| Comment | Post #281971 |
@coquelicot It's not complicated at all assuming you got the stuff already :) Though a high quality directional coupler costs a bit. Tracking generators are very easy to use, just attach two coax to input & output on the spec, then click on the button that says tracking generator, and that's pretty ... (more) |
— | almost 3 years ago |
| Comment | Post #282139 |
Also keep the reverse voltage in mind. 60V is too much for standard Schottky. Though shouldn't the coil voltage ideally get converted down close to 12V with a step-down? I haven't worked much with bigger contactors, but plain relay coils don't work reliably at all if you stray too far from their nomi... (more) |
— | almost 3 years ago |
| Comment | Post #282053 |
@Olin Lathrop So essentially the box would have to become a "mini EMC lab" :) Though large enough to not be in the near field, so not so "mini" any longer either. Maybe the easiest solution here might actually be to do the measurement outdoors in the open. (more) |
— | almost 3 years ago |
| Comment | Post #282053 |
One crazy idea I have: what if I mount the antenna inside a large metal box? So it is grounded but inside a Faraday cage. Then the environment would be the same and no reflections from walls or people. (more) |
— | almost 3 years ago |
| Comment | Post #281974 |
Yeah maybe nearby walls could be an issue. When I did this I had the antenna mounted vertically against a metal plate surface approx 300x300mm but the fixture was placed around 1-2 meters from a wall. Consisting of plaster, not reinforced concrete, but still. Maybe if I use one that's 1x1m and keep i... (more) |
— | almost 3 years ago |
| Comment | Post #281971 |
@Andy aka The purpose here is to measure pre-made antennas from various manufacturers to see if they can be used for the specific frequency. Still, if EMI is the cause, then moving the fundamental to some quiet band won't be reliable either, because I'd still get harmonics from TV/radio broadcasts e... (more) |
— | almost 3 years ago |
| Comment | Post #281247 |
The aim of this site is surely to be newbie-friendly to _electrical engineering newbies_ not to _general electronics newbies_. That means we should welcome engineering students or fresh out of school EE to ask questions here. If such users feel unwelcome, we are doing it wrong. If some John Doe who i... (more) |
— | almost 3 years ago |
| Comment | Post #281540 |
@coquelicot It means buying from component traders instead of the usual well-known vendors. There is a huge market of people buying and selling electronic components similar to stock trading. It's the last resort where you go when you can't buy obsolete parts from a trusted source. And it is filled ... (more) |
— | about 3 years ago |
| Comment | Post #281540 |
What makes you think it is fake in the first place? Did you buy it from the spot market? (more) |
— | about 3 years ago |
| Comment | Post #281444 |
Except it's not wands they are waving, it is 1/2 wave antennas! (more) |
— | about 3 years ago |
| Comment | Post #281437 |
I'm hardly an expert on antennas, just wondering how these hobbyist modules went from hobbyist status to reference design status... Here's an interesting article on the topic though: https://www.hindawi.com/journals/ijap/2018/5172960/ (more) |
— | about 3 years ago |
| Comment | Post #281437 |
What makes you think that antenna _is_ properly designed though? I hear nothing but bad things about these ESP32 modules. Anyway, you want an antenna to radiate, but your don't want regular traces to radiate. (more) |
— | about 3 years ago |
| Comment | Post #281246 |
Nobody dismissed anyone...? The question sits at 5 up-votes, 0 down-votes. I'd be curious to learn the reason too but nobody seems to know. (more) |
— | about 3 years ago |
| Comment | Post #281289 |
It's common that automotive MCUs come with custom markings. So that might not be a part number at all, only some program version. Any semiconductor company logo on them? Could also be a custom SoC or FPGA. (more) |
— | about 3 years ago |
| Comment | Post #281246 |
Li/Ion and LiPo are generally around 3.8 - 4V somewhere though, at least modern ones. And I think 3.3V goes back to the early 1990s somewhere, it probably pre-dates such batteries. So this doesn't explain where 3.3V comes from, specifically. I think this rather has to do with CPU core voltages and CP... (more) |
— | about 3 years ago |
| Comment | Post #281249 |
Why would you bend them in the direction of that picture though? Are you using heatsink? (more) |
— | about 3 years ago |
| Comment | Post #281165 |
In this case it is LoRa, which is supposed to use spread spectrum to compensate for high output power, so I don't get why the harmonics are that prominent. It's max 14dBm carrier if I remember correctly. (more) |
— | about 3 years ago |
| Comment | Post #281165 |
Just curious since my experience (I'm definitely not a RF designer) is that PI filters are mostly used for general EMC, like when you need to block emissions over a very broad frequency range. But harmonics are specific and you know where they will be at, so why not just get rid of them. (more) |
— | about 3 years ago |
| Comment | Post #281165 |
What's the reason you'd pick a PI low pass over a Chebyshev one? I thought Chebyshev were ideal since they give a much steeper dip after carrier? (more) |
— | about 3 years ago |
| Comment | Post #281144 |
In my opinion you can't really solder 0603 or smaller with the standard tips, nor fine pitch QFP, QFN etc. I always use a small tip for most things SMD. (more) |
— | about 3 years ago |
| Comment | Post #281066 |
@coquelicot You need to go some 30-40 dgr C higher for RoHS solder. However, if you have the possibility to set the temperature manually, you put it much higher than the melting point anyway, which is the temperature that affects the tip life. Leaded melts around 180, RoHS around 220 and I put the i... (more) |
— | about 3 years ago |
| Comment | Post #281083 |
Your 6th harmonic are over the spurious emission limits on a LoRa? That sounds strange, did you deviate a lot from reference designs? How many dBm are the harmonics at and what's your carrier output power? (more) |
— | about 3 years ago |
| Comment | Post #281083 |
I guess question #1 here is: is this a simplex or duplex radio? Any antenna switches etc present? (more) |
— | about 3 years ago |
| Comment | Post #281070 |
@Mu3 I think the debacle ended when LT merged with AD. There's no such database of part markings AFAIK, though some manufacturers provide a cross ref service on their site. In practice this is about asking a veteran EE - "I need a buck/boost part, who should I check with?". Or you can ask this of an ... (more) |
— | about 3 years ago |