Activity for Lundin
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| 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 4 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 4 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 4 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 4 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 4 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 4 years ago |
| Edit | Post #281070 | Initial revision | — | about 4 years ago |
| Answer | — |
A: Why do DC/DC switching controllers seem to favour the buck-boost topology over similar ones like Cuk, SEPIC and Zeta? I'm not sure there's a technical reason, except usually the offered parts are multi-topology and then they could be listed as buck-boost while they at the same time could as well be used as flyback, SEPIC etc. This seems to be the case for TI and Maxim, which at a glance seem to call everything "... (more) |
— | about 4 years ago |
| Comment | Post #281064 |
@mrwavelets So the MOSFET is not there to give a higher voltage needed for the amplitude? In that case it isn't necessary, since your particular part can drive a relatively high current directly. (more) |
— | about 4 years ago |
| Comment | Post #281064 |
How do you intend to connect it to the MOSFET? If you mean to have the 555 timer on the gate, then you'll have to be very careful with which part to pick, since most MOSFET aren't fast enough to live up to your realtime spec. What 555 timer are you using? In case it's a single chip IC, there should b... (more) |
— | about 4 years ago |
| Comment | Post #281059 |
This is far from my area of expertise, but have you checked Analog Devices? They have tonnes of more or less exotic amplifiers. https://www.analog.com/en/products/rf-microwave/rf-amplifiers.html. If you for example check their "Wideband Distributed Amplifiers" they have lots of parts explicitly desig... (more) |
— | about 4 years ago |
| Comment | Post #281061 |
Anyway, I would strongly suspect that the root of your problem is the solder station itself. What brand and what temperature are you using, assuming it is temperature controlled in the first place? Coating the tips when not using them is a good idea btw, so keep doing that. (more) |
— | about 4 years ago |
| Comment | Post #281061 |
The flux core in RoHS solder is very unhealthy too. So in case you worry about your kid putting it in their mouth, it's not a better alternative than leaded. (more) |
— | about 4 years ago |
| Edit | Post #281021 |
Post edited: More relevant tags |
— | about 4 years ago |
| Suggested Edit | Post #281021 |
Suggested edit: More relevant tags (more) |
helpful | about 4 years ago |
| Comment | Post #281021 |
And then finally a question along the lines of "what would happen if all digital currency gets destroyed" might also be suitable for Scientific Speculation. Now, if you are looking for a _debate_ about why digital currency is bad, then none of these sites are suitable, since this is a Q&A platform. (more) |
— | about 4 years ago |
| Comment | Post #281021 |
@JohnDoea There's several separate questions here: is it electrically possible to have some manner of global EMP event - that question could be asked either here or on the Physics site. If it's related to power grids etc, then here. If it's related to astronomy or nature forces, then the physics site... (more) |
— | about 4 years ago |
| Comment | Post #281021 |
I think this is more related to astronomy than EE. Although somewhat on-topic here, the question would probably have been more at home at https://physics.codidact.com/. Like for example, is it feasible that some really big comet passing close to earth has a wildly different potential and then cause s... (more) |
— | about 4 years ago |
| Comment | Post #280675 |
@Chupacabras Aim for one with 20mA, that's more industry standard. Also for 1st source I'd probably pick a silicon vendor with more self-respect than someone who calls themselves "MaxLinear" - there's nothing wrong with their parts, it's Sipex/Exar/whatever, they change name every year. But I laugh w... (more) |
— | over 4 years ago |
| Comment | Post #280894 |
@2kind So toss in a NPN and a pull resistor to the right side. Signal polarity should be trivial to fix. Also, if you don't need the voltage divider R2 you could simply use an internal MCU pull resistor. (more) |
— | over 4 years ago |
| Edit | Post #280894 |
Post edited: |
— | over 4 years ago |
| Edit | Post #280894 | Initial revision | — | over 4 years ago |
| Answer | — |
A: Isolated Digital Input - Overvoltage protection > Step 1: Since 3V3ISO would be LDO driven I would probably add a diode with the anode connected to the LDO output and a cathode connected with the LDO input to prevent the LDO to have output higher than the input. Based on my experience they tend not to love that. I haven't post that because I haven... (more) |
— | over 4 years ago |
| Comment | Post #280675 |
@Chupacabras Did you try the above mentioned XR46010ISBTR? Looks fairly compatible, though I'd double check the pinout because SOT-23 pin numbers aren't that well standardized. (more) |
— | over 4 years ago |
| Comment | Post #280672 |
@Chupacabras The 90mA current is an odd case, most LEDs are rated at 20mA. Also, you can get extreme super bright LEDs that shine like the sun with several candela at 20mA, why focusing on the LED is easier. (more) |
— | over 4 years ago |
| Comment | Post #280672 |
It looks like a board where anything can fail at any moment though... Anyway, why not just pick a brighter LED? So much easier. (more) |
— | over 4 years ago |
| Comment | Post #280672 |
Hmm, I don't think failing parts is necessarily the problem given the pics. The solder job is truly awful and besides you got corrosion of some kind all over, to the point where I would suspect that the board is water damaged. (more) |
— | over 4 years ago |
| Comment | Post #280713 |
You can easily answer this by not connecting the probe ground to the DUT and measure something, then connect the ground and measure again. The signal that looks like crap is the one that you don't want. (more) |
— | over 4 years ago |
| Comment | Post #280675 |
@Chupacabras As noted, this was a PNP part but you need N-channel. Just search for SOT23 LED Driver and you get plenty of results. If you wish the exact part, then you have to put more effort into the question, adding the print on the IC and preferably also a photo. (more) |
— | over 4 years ago |
| Edit | Post #280672 |
Post edited: |
— | over 4 years ago |
| Comment | Post #280675 |
Closest match on Mouser appears to be XR46010ISBTR with NPN. SOT-23 pinout standardization leaves a lot to be desired though, so I'd be very careful double-checking the pins of your layout symbol vs datasheet. Don't trust the schematic pin numbers. (more) |
— | over 4 years ago |
| Edit | Post #280675 |
Post edited: |
— | over 4 years ago |
| Edit | Post #280675 |
Post edited: |
— | over 4 years ago |
| Suggested Edit | Post #280672 |
Suggested edit: (more) |
helpful | over 4 years ago |
| Edit | Post #280675 |
Post edited: |
— | over 4 years ago |
| Edit | Post #280675 | Initial revision | — | over 4 years ago |
| Answer | — |
A: Name of this current limiting device It is some manner of BJT or MOSFET LED driver similar to for example this: NCR402T (just a random example, this one was PNP). They are literally called "SOT23 LED driver" (Mouser calls them "SOT23-3 LED Lighting driver"). Which exact part you have, I can't tell without marking. Plenty of manufact... (more) |
— | over 4 years ago |
| Comment | Post #280672 |
Is R1 really 1 ohm? Then what purpose does it fill? (more) |
— | over 4 years ago |
| Comment | Post #280595 |
Semiconductor companies in general and NXP in particular let their "FAE" play around with evaluation boards and write app notes on their spare time. That is, engineers with incredibly broad but rather shallow knowledge. Mostly these should be regarded as some hints to get people started (with the com... (more) |
— | over 4 years ago |
| Comment | Post #280586 |
As for the question "what is AC frequency", that's a valid question. Alternating currents means you have several phases (simply put: several signals/wires) between which the current alternates. The current in each phase comes as a sine wave and the "AC frequency" is simply the (2*PI) period of the si... (more) |
— | over 4 years ago |
| Comment | Post #280586 |
This entirely depends on what motor that sits inside the oven and how it was designed. I wouldn't assume that every microwave that has ever been made is using the same kind of motor. You'll have to come up with some manner of partnumber or preferably a datasheet of the motor, or I don't think this qu... (more) |
— | over 4 years ago |
| Comment | Post #280582 |
@Olin Lathrop I don't think there's any relation between the number of categories and the site activity. That site like several others struggles because it had too few veteran/enthusiast users from the start. That being said, we aren't exactly drowning in new posts either, so yeah maybe we should wa... (more) |
— | over 4 years ago |
| Comment | Post #280582 |
@Olin Lathrop The benefit of a different category is that we can apply different posting rules there. For example if someone wants help to trouble-shoot their program, we'll want a minimum code example and/or the relevant schematic page only. However, if they are looking for a design review we might ... (more) |
— | over 4 years ago |
| Edit | Post #280582 |
Post edited: |
— | over 4 years ago |
| Edit | Post #280582 | Initial revision | — | over 4 years ago |
| Answer | — |
A: How about a new section for code reviews? Regarding scope of embedded systems/firmware When we released Software Development, I made a push to make all forms of embedded systems programming off-topic and re-direct such to this site. The reason for this is is my experience from the "embedded" tag over at SO, where I'm one of the top use... (more) |
— | over 4 years ago |
| Comment | Post #280564 |
@ Monica Cellio Embedded systems programming is currently off-topic at Software Development but on-topic here. (more) |
— | over 4 years ago |
| Comment | Post #280479 |
The 6A current limit sounds like hogwash. The human body has too high resistance to ever get close to currents like that. And the currents are what matter here, not the voltages. (more) |
— | over 4 years ago |
| Comment | Post #280479 |
(Disclaimer: I don't know much about medicine save for a CPR class.) To stop the heart you just need to make the (I think they are called) beta receptors freak out, which only takes a relatively small current. These control the heart rhythm and if they stop acting reliable you get a heart failure. Th... (more) |
— | over 4 years ago |
| Comment | Post #280454 |
The way I usually do this is to buy pre-programmed MCUs for high volume products ~1000pcs/year, keep the SWD connector footprint on the board but don't mount it. For products of lower volumes or products where you expect a lot of software releases, keep the connector and use an in-circuit programmer.... (more) |
— | over 4 years ago |