/ohm/ - Electronics General: Happy New Year Edition

[Anonymous No.2738353]

Previous thread dissolved:>>2730264
>I'm new to electronics. Where to get started?
It is an art/science of applying principles to requirements.
Find problem, learn principles, design and verify solution, build, test, post results, repeat.

>Incredibly comprehensive list of electronics resources:
https://github.com/kitspace/awesome-electronics
Additional resources below:

>Project ideas:
https://adafruit.com
https://instructables.com/tag/type-id/category-technology/
https://makezine.com/category/electronics/
https://hackaday.io

>Don't ask, roll:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png

>Archive of Popular Electronics magazines (1954-2003):
https://worldradiohistory.com/Popular-Electronics-Guide.htm
>Microchip Tips and Tricks PDF:
https://ww1.microchip.com/downloads/en/devicedoc/01146b.pdf
>Li+/LiPo batteries required reading:
https://buster-spb.ru/files/SAFT/li-ion_user_manua.pdf

>Books:
https://libgen.rs/

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors (arguably has minor issues with mains grounding)
Horowitz and Hill, The Art of Electronics

>Recommended Design/verification tools:
KiCAD 6+
Circuitmaker
Logisim Evolution

>Recommended Components/equipment:
Octopart
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>More related YouTube channels:
mjlorton
jkgamm041
EcProjects
Photonvids
sdgelectronics
paceworldwide

>microcontroller specific problems?
>>>/diy/mcg
>I have junk, what do?
Shitcan it
>consumer product support or PC building?
>>>/g/
>household/premises wiring?
More rules-driven than engineering, try /qtddtot/ or sparky general first
>antigravity and/or overunity?
Go away

[Anonymous No.2738576]

bump?

[Anonymous No.2738751]

Can I just put a blob of solder down to replace the copper pad I ripped off on my 3D printer heated bed?

[Anonymous No.2738803]

>>2738751
Uh, no, not directly at least. You need to scrape off the solder mask and expose more of that trace so you can solder onto that.

[Anonymous No.2738806]

jews rock!

[Anonymous No.2738807]

>>2738751
what would the solder stick to, if not the copper pad that you ripped off?
as is standard practice for this sort of event, you're best off scraping some of the solder mask off a nearby trace that was connected to the pad and soldering a bodge wire from there. Securing the wire and/or the component floating atop the missing pad with adhesive if necessary. the uv-cure stuff is good for this.

or use this as a good excuse to buy a mains-powered heated bed

[Anonymous No.2738825]

Henlo gamers, piezo contact mic guy from a few threads ago. I built the first mic, and it works. Here's a test in which I pressed the mic against my desk with my index finger while turning the gain dial up slowly - the constant hum is my USB desk fan, the intermittent scratching is the potentiometer turning, and right near the end the super low thumping is my pulse, picked up through my finger: https://vocaroo.com/1nrwsGcbl533
Not really sure what to do about the output level. Theoretically the mic can output 36V signals, which is a far cry from the 1.734V of line level, and from the 100mV of mic level. I think it should be fine, because whatever it's plugged into should* just clip the signal, but it's got me a bit noided. Any thoughts?

I know the flux is ugly. I want to clean it, but IPA won't touch it and I don't have MG Chem's proprietary flux cleaner. It's non-corrosive at least. Also, the recording was with the case closed. With the case open, as pictured, interference is an issue. The inside of the case, except for the top and bottom plates, is coated with the conductive paint I've been developing, mentioned a thread or two back. Works well.

[Anonymous No.2738828]

[Anonymous No.2738833]

>>2738825
Here's what it currently looks like assembled. I want to do the faceplate and contact plate in laser-cut brass, but can't yet afford it so I made some for the prototype out of some copper-clad board. The backs of the plates has a layer of copper tape to provide that face with EMI shielding since it's single-sided copper-clad and I have the copper side out.
Thank you to everyone who gave feedback on the circuit, you were immensely helpful.

[Anonymous No.2738879]

I'm struggling to not make a possibly poor financial decision

[Anonymous No.2738880]

I had partial success cutting out pcb traces. But it takes multiple parts to clear the copper out of the dent. I can't find a two blade knife like pic related, where the angle or gap is adjustable. If the copper is still too tough, I would consider using such a tool to cut masking tape that will keep citric acid etchant off.

[Anonymous No.2738882]

>>2738879
They're on zlibrary unless you really really want to pay the publisher

[Anonymous No.2738884]

>>2738882
I work in the defense industry and I can't bring external files into our network (and I'm not retarded enough to pirate shit on the company network), so I have to use physical copies

[Anonymous No.2738917]

>>2738880
>it takes multiple parts to clear the copper out of the dent

wow.
you just make a V cut.
takes 1.8 seconds and it's guaranteed clean.

[Anonymous No.2738922]

>>2738884
It's cheaper to buy a laser printer + paper and print all three books yourself.

[Anonymous No.2738925]

>>2738917
Do you use a stencil?

[Anonymous No.2738931]

>>2738884
So print the parts you care about. Why do you need to read them at work?

If you download them you can either print them or buy them if you find them worthy, but most people read a book once then it sits.

[Anonymous No.2738948]

>>2738931
>most people read a book once then it sits.

Perhaps that is true with the internet, but back in the day I didn't "read" a highly technical book and never touch it again. Certain sections got looked at over and over, especially if I didn't use that information for a year or more. On the other hand, I do know guys (like my damn brother) who seem to retain everything they ever learned.

[Anonymous No.2739024]

>>2738948

[Anonymous No.2739025]

hmm

[Anonymous No.2739036]

10V peak per cell? that's a lot for the lithium ions the bms ic is designed for, is this meant to protect against inductive spikes? i don't really want to get 120v mosfets for something that's otherwise fine with 60v mosfets, i might just slap some zener diodes in there and call it a day

[Anonymous No.2739037]

>>2739036
also they use a source follower instead of a linear regulator
lower quiescent current i guess

[Anonymous No.2739053]

I know everything about theory, how to make circuits, how to produce them etc. What I lack is purpose, an objective, and an idea. Do you have advice on that ? I don't know what to make, all I know is I want to make something.

[Anonymous No.2739054]

>>2739053
What you're really asking is a philosophical question. Spend 40 days and nights innawoods to clear your mind.

[Anonymous No.2739100]

>>2739053
Software fag here, I have identical struggles. I find some inspiration reading books, papers, and blogs. I can also generate ideas when my mind wanders at work. Something magical about caffeine and boredom.

[Anonymous No.2739118]

Can someone suggest me a connector rated for at least 10 amps with some locking mechanism? Preferably with screws like vga.

[Anonymous No.2739122]

>>2739053
lack-of-idea guy

[Anonymous No.2739153]

>>2738884
doesn't DoD shit pay out the ass? $500 should be trivial if you're gainfully employed

[Anonymous No.2739155]

>>2739053
make test equipment so you can have a pro-level lab setup when you finally make up your mind

[Anonymous No.2739190]

>>2738884
Can you bring it in on an e-reader?

>>2739053
The journey is the goal. As the other anon said, making your own lab equipment is a great start. Especially a function generator and power supply, but also more tangentially related things that might come in handy, like a spin-coater, reflow-plate/oven, furnace, even CNC machines like a laser, 3D printer, router, pick-n-place, etc. Even a full chemistry setup for plating your own through-holes is an option.

>>2739118
Why not just use a DB9? Its pins are rated for like 3A each, so you could put 4 in parallel for positive and negative each. The remaining pin could be a 1-wire pin for communication to and from the PSU.

[Anonymous No.2739201]

>>2739190
>Its pins are rated for like 3A each
Oh didn't know that, thanks.

[Anonymous No.2739219]

>>2739201
I wouldn't trust shitty chinese DB9s with loose pins to have the same current rating, but considering 2.1mm DC jacks are used for 10A I think it would probably be fine even if you are exceeding the recommended rating. Make a milliohm meter to measure the contact resistance if you're worried.

[Anonymous No.2739238]

>>2739190
> db9 rated for 3 A
Maybe a real db9, I doubt a new chinese knock-off would have such a rating.
Try and get one off older, legitimate, equipment.

[Anonymous No.2739252]

So I have this SSD with a broken sata port, been sitting in a drawer unused for years. I had the idea yesterday that I could just pull the port from an old laptop drive and solder that into place. Today I got to work, removed the broken port and salvaged the port from a dead HDD. And of course the power and data connectors are reversed for the HDDs so they don't fit the SSD. Fuck.
Aren't these things made to some standard? Like, you can't just decide to swap the ports around, right?

[Anonymous No.2739255]

>>2739252
Post pics.

[Anonymous No.2739258]

>>2739252
It has a make and model, post that too.

[Anonymous No.2739268]

>>2739252
>the power and data connectors are reversed

sure, i believe that.
but if you just flip 'em 180 degrees, then they'll match exactly.

[Anonymous No.2739277]

>>2739255
Here you go

>>2739268
Yes, but then the pads need to be on the other side of the board

[Anonymous No.2739278]

>>2739153
It does pay out the ass, if by that you understand it to mean it pays like shit.

[Anonymous No.2739279]

>>2739277
The connector you salvaged is for a 3.5" drive, probably mounted on the opposite side of the PCB. You need a connector for 2.5" (7+15).
https://www.aliexpress.us/item/2251832861368508.html

[Anonymous No.2739280]

>>2739279

[Anonymous No.2739282]

>>2739279
>The connector you salvaged is for a 3.5" drive
Uhh, no, it's from a 2.5 drive. Picrel the board I took it from and I even have another of the same model.

[Anonymous No.2739283]

>>2739282
You could flip it and solder upside down, but you have to be really careful about pulling traces when you plug it in. Doesn't really matter how the connector is mounted as long as the signals are going to the right place. In practice, you don't even notice the orientation because you just flip the SATA/power cables when you connect it.

[Anonymous No.2739326]

If I want to do electroplating at home just for fun, what should I be using as the anode and cathode? I messed around using alligator clips and plated a quarter in copper but it also made a bunch of rust in the water because of the material of the clips.

[Anonymous No.2739353]

>>2739326
Coat your piece in graphite and use it as the cathode, and use nickel as the anode.

[Anonymous No.2739354]

>>2739353
and don't put the alligator clips in the solution.

[Anonymous No.2739463]

>>2739326
if copper plating, use copper as your anode. it doesn't really matter too much the quality as long as it's not an alloy. Use copper wire to suspend your part in the solution. Cathode is your part to plate. Safer Solutions' copper conductive paint is often recommended for non-conductive parts.

[Anonymous No.2739473]

>>2739463
>>2739354
>>2739353
Thanks, I'll make some adjustments. If yall are doing copper plating what copper do you use/buy for it? I've just been messing around so I was just using a penny but yeah that doesn't seem to be working super well

[Anonymous No.2739493]

>>2739473
solution of copper sulfate with a little bit of sulfuric acid added, exact ratios can be googled.

[Anonymous No.2739511]

>>2739463
> copper conductive paint
I wonder if that’s what PCB manufacturers use to make plated-through holes.
Then they dip it in a plating solution as long as they can make an electrical connection to the plate thru area and use it as a cathode?
I though of maybe using tiny rivet-like thing but when I examine most thru-hole boards I don’t see anything like that. On some, I do: some of the ATX power supplies used rivet-like thing for the main output lines on the PCB.

[Anonymous No.2739526]

>>2739511
>I wonder

in less time that it took to write your speculation, you coulda googled and known the complete answer.
you may be an anachronism, an obsolete PG-man (pre-google) and thus on the list for erasure soon.

[Anonymous No.2739531]

>>2739473
Pennies aren't good because post-1982 are 97.5% zinc. Use copper pipe or plumbing fittings (type L) or copper foil.

[Anonymous No.2739542]

>>2739326
I just use some of that 7-core grounding wire. Personally I set my PSU's current to be quite low, as that reduces the effect of the suboptimal conductivity of my solution, allowing for a more even coating. But doing that does make it take a while.

>>2739353
>use nickel as the anode
Why? The nickel might not dissolve if you don't push the voltage too high, but even then you'll be producing oxygen gas at the anode and causing the pH of the solution to decrease. It likely will dissolve the nickel though, since it's far easier to electrochemically dissolve nickel than to electrolyse oxygen from water. You're far better off just using copper as the anode and dissolving it at the same rate as the copper is being plated, that way your solution's concentration remains constant. If you do want to use an inert anode that won't dissolve, I highly recommend buying platinum or MMO electrodes like what Scrap Science uses. Personally I bought some pure platinum wire that I use for turning copper sulfate into sulfuric acid, among other things.

>>2739493
For reducing pH, you can add sodium bisulfate if you can't buy sulfuric acid where you live. Citric acid should work too, though citrate is not a bystander with regards to copper. It may well change the surface finish and evenness of the coating. Same for adding surfactants.

>>2739511
No, they use palladium-catalysed electroless copper plating. These palladium solutions are expensive to buy, so I'd instead recommend using electroless silver plating if you want to attempt this at home. That said, I've heard the presence of silver can interfere with the etching process, so maybe you need to mask the board off to prevent silver getting plated on areas that you plan on etching. Either way, once the initial electroless plating is put down, you electroplate a thicker layer of copper atop the rest.

[Anonymous No.2739548]

some people do use PCB rivets but there's not a whole lot of a point to it, since you can just solder a wire through, or use a component leg.

[Anonymous No.2739568]

>>2739526
> pre google
altavista was down again.
I mean something I could emulate at home. I’ve watched some documentaries on thru-plating but that’s the one thing they weren’t allowed to show as it was a trade secret and proprietary. I also looked at how they manage plate plastic buttons, but that was a trade secret, too. So, what they actually use might be different from mfr to mfr.

>>2739542
> palladium
That sounds expensive. With that paint, I was thinking after I etch, I could paint the inside of the holes with that safer solution’s paint, and then build it up using electrodes in a copper solution, attaching some alligator clips to the traces and just dipping it for a minute or two.

I still haven’t found out how they get the copper layer on the PCB fiberglass/paper epoxy/phenolic substate in the first place. Not sure if it’s plated on, glued on, or if it’s just pressed on before the board is cured.
And, if glued, where to buy high temperature glue like that, same with the epoxy itself.
Obviously, this would help me repair pulled and burned-off traces, fix etching (and design) fuck-ups on pcbs while hopefully still looking professional without kynar wire and glpt everywhere.

>>2739548
> rivets
That looks skookum as hell, but it seems to be more for 40’s and 50’s era electronics, judging by the size.

[Anonymous No.2739572]

>>2739568
>That looks skookum as hell, but it seems to be more for 40’s and 50’s era electronics, judging by the size.
You can get them in all different sizes, from big 2.5mm ID down to like 0.3mm ID. They're kind of a pain in the ass to install.

[Anonymous No.2739580]

>>2738353
What does mean when the pin diagram of an IC are not marked or given any description(>picrel.png), or when they have a ⁓ symbol.
Thanks.

[Anonymous No.2739584]

>>2739548
>that drill/router alignment
Oof. Also it looks like he just routed the vector paths directly on the borders of all his copper shapes, making his pads and traces thinner than they should have been. I wonder what CAM software there is for making routing toolpaths from a PCB file, at the moment with my laser I export as an SVG and do a bunch of processing to turn that into an SVG that lightburn can properly read. But something that could take a gerber file would be much better. UVtools managed to do it for MLCD photoresist exposure, be nice if someone did the same for lasers and routers.
>there's not a whole lot of a point to it, since you can just solder a wire through
It matters for components that are flush against the board, like electrolytic capacitors and pin headers. There's no room to solder them on the front side. Personally I just design my 2-sided boards to only make connections to the back side of components, I even wrote a python script that deletes THT component pads on the same side of the board as the component. Even though I could solder on the front side for THT ICs or diodes or whatever. Plated/riveted through-holes also make the solder connections stronger mechanically.

For vias I've dabbled in hand-riveting solid-core copper wire and soldering wires. Soldering has the problem that they make lumps on the board itself, and if you're soldering a component nearby they can reflow and fall out.

[Anonymous No.2739586]

>>2739568
>I was thinking after I etch, I could paint the inside of the holes with that safer solution’s paint
You absolutely can do this for a diy job, and I see people do this on occasion. But it's a pain to get a sufficiently even coating. I tried this once by turning sticks I'd found in my garden into charcoal, grinding them up with a rock, and mixing it with paint or glue. The grind wasn't fine enough, but with a fine enough charcoal powder and a fluid enough paint you could definitely blow it through the holes on a PCB, though on a large board with dozens of holes I suspect it would get tedious. The only thing to watch out for is whether the paint will handle the temperatures of soldering. It doesn't particularly matter since there will be copper atop them, but it's something to keep in mind.

I think the copper is bonded to the FR4 from heat and pressure, like how carbon fibre aircraft parts are cured in an autoclave.

>>2739580
For a bridge rectifier, one pin is the positive output, one pin is the negative output, and the remaining two have no choice but to be the alternating current inputs. Take a look at a bridge rectifier schematic to confirm. These alternating current inputs are often displayed with the ~ symbol, because it looks like a sine wave. It doesn't matter which of these is live or neutral.

[Anonymous No.2739587]

>>2739580
That's not an IC, it's a bridge rectifier. The unmarked pins(or marked with ~) are the AC inputs, + and - are for the DC coming out.

[Anonymous No.2739589]

>>2739587
bridge rectifiers are diodes, and diodes are semiconductors. bridge rectifiers are ICs.

[Anonymous No.2739591]

>>2739589
Technically you are not wrong but a bridge rectifier isn't what most people here think about when they mention ICs.

[Anonymous No.2739600]

>>2739586
>>2739587
>>2739589
>>2739591
Thanks, very appreciated.

[Anonymous No.2739601]

I have this potentiometer in my oscilloscope that's getting worn and needs replacement. It has two 10k gangs, but they're separated by 180°. The thing can do full rotations. In size it looks like a standard ~16mm RK163 potentiometer, the nut on it isn't metric. It says 10KBX2 on one side, 546t on the other, and what looks like ALPS is embossed on it. But it doesn't seem to be a part currently being sold by them. Any ideas where to get one?

[Anonymous No.2739604]

if i replace a condenser motor and a compressor and whatever other little things, can my ac unit run forever? why do people replace them? sounds expensive.

[Anonymous No.2739606]

>>2739601
Don't know, but did you douse them in contact cleaner and spin them to and fro 9000 times yet?

[Anonymous No.2739608]

>>2739604
It'll run until the refrigerant line bursts, the compressor fails, the condenser fan overheats, the condenser cooling fins dissolve, the drain float switch gets stuck, the evaporator turns into mold and the contactor melts.

[Anonymous No.2739617]

>>2739604
>compressor and whatever other little things
The compressor is the most expensive part of your AC system.

[Anonymous No.2739640]

>>2739606
Not yet, but it's an old scope and I want to get backups for parts just out of principle. The two pots that are really dodgy are different, pic related is a 1k of the same model but the dodgy ones are 10k (and say 546 not 545 on the side). The service manual calls them:
>V12L5 (PVB) N10KOHM SHAFT18
The pot isn't mounted on the panel at all, it relies on the PCB mounting for stability, which consists of the three main pins but also a structural pin at the back. I can't seem to find one of these on octopart, or in the catalogues of Alps, Bourns, or Panasonic. Does anyone recognise this manufacturer's symbol? Searching for V12L5 pots gives me a few old multi-sectioned pots for audio stuff, but nothing like this. I gave the two bad pots a liberal soaking of IPA and a good twisting, we'll see if that fixes it but they're the vertical-offset pots for X and Y in an 80s scope so they're not going to last forever.

[Anonymous No.2739661]

>>2739640
I made an effort to find it but failed. It looks like that pot can be disassembled if you want to get it really clean. If you want to go crazy, get a new pot and mount it to a custom adapter PCB that sits on top of the old footprint.

[Anonymous No.2739665]

>>2739640
It’s probably a voltage divider
Maybe you could replace it with a rotary encoder and d to a converter

[Anonymous No.2739671]

>>2738353
One of these led spotlights come with the next circuit,
If isn't too much bother , can explain me how does it works,please?
The varistor 07D271K is rated at 175V rms, so afaik, this would work as some kind of clipping diodes to hold the voltage between certain limits, the MB10F rectifier, the capacitor maintains the output level filling the possible gaps of the rectifier at the cycle change, I'm guessing the 150k resistor is to avoid any peak current, but this does work as I'm writing or not?
Also
Where is the DC-DC part to change the 120 to 5v? the led plate only has the pins to fit the output, but it does not have anything on it.
2nd also
is there a guide/book to recognize the circuit from the board? I have always failed to do so well, often got stuck with a resistor leading to nowhere or some track vanishing or invisible.
Thanks.

[Anonymous No.2739672]

>>2739671
I forgot, what voltage level would I get from this?(assuming nominal 127V)

[Anonymous No.2739688]

>>2739671
The schematic is wrong. A series cap after the rectifier is an open circuit because caps block DC. The other side of the cap is labeled negative which is wrong (relative to the load), as well as 0V labeled as positive.

The series resistor should be on the positive output from the rectifier, and the cap should be in parallel with the load.

How many LEDs are in the spotlight? What's the make and model, or can you see any markings on the PCB?

[Anonymous No.2739701]

>>2739688
Let me check the pcb; one spotlight comes with 20 and other with 6.

[Anonymous No.2739709]

>>2739701
The part of the source says
>M849-1
>94V-0
>E239807
The 6 leds one
>BS-2863-6C-39.8
The 20 one
>38.3-20C-1(or T)
>ZEB584
>LV40064-4
I guess this all marks are from the manufacturer, but I can't tell which one is relevant.

[Anonymous No.2739720]

>>2739709
>Where is the DC-DC part to change the 120 to 5v
I'm guessing that the forward voltage of the LEDs is higher, and they're wired in series so the voltage stacks. The 150k resistor limits the current to the LEDs from the 170VDC after the rectifier.

[Anonymous No.2739750]

>>2739720
>they're wired in series so the voltage stacks
And how this won't blow out?
I get the voltage divisor part here, but each led would see 170V-V_on,170-V_on-V_on..., but except for the last ones, they would be charged with way more voltage than they need.
In fact I check the leds, and all they like you say in series.

[Anonymous No.2739757]

>>2739661
>get a new pot and mount it to a custom adapter PCB that sits on top of the old footprint.
I guess that's an option, this pot seems a tiny bit taller than the standard metric 9mm pots I've got lying around. Though my metric pots are horizontal-mount so don't have the additional mounting pins I'd want.

>>2739665
It's part of an analogue section in a CRT oscilloscope, it handles the Y offset of the signal. Doubt it's below the ~5V that digipots can handle.

>>2739750
Rectified 120VAC mains makes 170VDC. Voltage adds in series, so 50x3V single-emitter white LEDs will have a total voltage drop of 150VDC. Then your current limiting resistor just has to drop 20V.
Watch a big clive video on taking apart a mains voltage light bulb, you'll see LED bulbs that use dedicated constant-current ICs with thermal throttling, LED chips with multiple series LEDs in each package, and also capacitive droppers where a series AC capacitor is used to reduce the heat production of the dropper resistor.

[Anonymous No.2739769]

Is it possible to create an adjustable differential amplifier based around just a dual op amp, with a single-gang pot for gain control? I've seen the "classic" circuit pictured, but it requires 3. Dual-gang pots are no good because the signals need to track perfectly.

[Anonymous No.2739782]

>>2739757
Thanks for the info about the voltage stacked, I will look for the clive videos.

[Anonymous No.2739783]

>>2739769
just use this for the differential, then the second op amp for gain control

[Anonymous No.2739784]

Hey anon, my schematic has become kinda messy, can I somehow replace all these wires with netlabels?

[Anonymous No.2739785]

>>2739784

[Anonymous No.2739787]

>>2739769
Just buy a monolithic instrumentation amplifier IC.

>>2739783
Not him, but the input impedance for that might be too low.

>>2739784
Yes. You can either use labels (keyboard shortcut “L”) or global labels (keyboard shortcut "mod+L", whatever your OS's modifier key is). Global labels have more options for their shape, which reflects whether they're an input, output, bidirectional, tristate, or passive. Global labels also work across hierarchical sheets.

[Anonymous No.2739789]

>>2739548
Thanks for bringing this to my attention. I'll give it a try.
Soldering the components from both sides looks dodgy as fuck and isn't viable for many connectors which are soldered flat to the PCB.
So I found the chinks have this to offer https://de.aliexpress.com/item/33057593993.html?spm=a2g0o.cart.0.0.16664ae4wA8AS0&mp=1&gatewayAdapt=glo2deu
My PCBs are around 1.7mm thick.
What would be the correct length here. I don't really get what chang is trying to convey with i.e. "M0.9-1.7 MIX". Is it a mix of different sizes?
Do I need some special tool to press em in?

[Anonymous No.2739790]

>>2739787
>keyboard shortcut “L”)
Great. Unfortunately it doesn't automatically remove the wires like I had seen with some other CAD programs.

[Anonymous No.2739792]

>>2739789
You pick the size not by length, but by the size of hole you need for your component legs to fit through. any one of them will be long enough.
> "M0.9-1.7 MIX". Is it a mix of different sizes?
they mean an assortment, that's probably the first picture.
>Do I need some special tool to press em in?
special tools do exist, but most people use a center punch (not the spring loaded kind)

[Anonymous No.2739798]

>>2739792
It says "stem length", so it seemed to me the selection is for the lenght of the rivets.
Chang makes it deliberately confusing so someone buys the cheaper option.
I'd propably get a refund if I chose that option in the expectation that I'll get the assortment. Gotta foster my inner chink

[Anonymous No.2739799]

>>2739798
>so someone buys the cheaper option
in the expectation that they'll get the same thing at a lower price than the other sellers

[Anonymous No.2739812]

>>2739688
> series cap after rectifier is wrong
Now hold on there hoss, you will definitely get stuff on the other side of that cap because that’s pulsating dc with a huge ac component. Picrel comes out of the rectifier.

[Anonymous No.2739821]

>>2739789
Personally I would get the dedicated tool, it ensures that the centre remains open for leads to easily pass through. I've had issues where the middle becomes folded a little and doesn't have room for a lead. Pic related are what the tools look like. No I don't know where you can buy them from the chinks.

Also, what kind of PCB manufacturing setup do you have? With 2-sided boards it can be pretty tough to get good alignment. If you're using a CNC laser/router or MSLA lightbox, the alignment can be done with jigs and fixturing. But if you're using transparencies or toner transfer, you've got to align it by hand. This can be done by drilling the holes first, or by drilling them between exposing the first and second layers, but it's kinda precarious to have your etch resist stretched across holes like that. If you're hand-painting then it's fine I guess, I've done it that way a few times.

>>2739812
But current will only flow one way through the rectifier. So if you put even the smallest load, the capacitor will saturate at the peak voltage, and block any further current passing through. Same reason you can't use a capacitive dropper with a single diode rectifier, at least not without an additional diode.

[Anonymous No.2739826]

>>2739821
>the capacitor will saturate at the peak voltage, and block any further current passing through
No, wtf, that's not how it works.
If you have a rectified sine wave the cap gets charged while the voltage is high and will help power the load while the voltage is low.

[Anonymous No.2739828]

>>2739821
>what kind of PCB manufacturing setup do you have?
I have this thing. It uses drill holes to align the board properly after flipping.

[Anonymous No.2739829]

>>2739784
>replace all these wires with netlabels?

you sure can.
but, for someone reviewing your circuit, it's frustrating as fuck to find matching labels.
but you can do a mixture of the 2 techniques by using buses.
this way the eye can easily follow the logic of the circuit, but the wiring is greatly simplified.
protip: you can use the bus wire even when there's only 1 or 2 exit points, as opposed the whole bus like in the pic.

[Anonymous No.2739833]

>>2739829
Not a solution for me unfortunately. The pins of the symbol have to be neatly laid out.
What would be helpful is if the label would indicate were it was coming from interchangebly - if that makes any sense.
What I mean is for example if Arduino D2 were to lead to 2A of IC1.
So D2 of the Arduino would indicate 2A, and the label on pin A2 of IC1 it would indicate D2.
Don't know why it doesn't do that automatically.

[Anonymous No.2739834]

Do you guys feel guilty for giving the chinks so much money?
Any experience with vendors like Digikey, or does this also just get manufactured in china?
Trying to place an order on Digikey I noticed shipping is fucking expensive, so I figure it only makes sense for larger order.
Are there maybe more hobby friendly vendors?

[Anonymous No.2739836]

>>2739834
I've always used Mouser but I'm probably dumb for that.
Depends what it is.

[Anonymous No.2739865]

>>2739834
Majority of components are manufactured in china. You could try and buy components from other countries, but even then you can't be sure if origin is actually accurate. Pic related I bought a relay from Omron that claims that the country of origin is Japan. It says "MADE IN CHINA" on relay itself. Personally I don't care. My government hates me and I don't care if me sending money to china hurts our economy. At least chinks still make things and service quality is also improving (as long as you don't buy absolute cheapest junk and then complain why it's shit). Doing electronics as a hobby in china is god tier
>https://www.youtube.com/watch?v=eKQe9ZqMcEY
Here in europe I only get rude grumpy parts distributors that don't even have all the parts you can get in china. Not to mention inflated prices.

[Anonymous No.2739869]

>>2739833
nets/traces/wires are not labelled by their connection points but rather their function/what its connectin to. doing what youre saying is kinda dumb because you dont know what that net is for. eg. you got a high speed signal that requires a special layout, during pcb editing you may forget due to ambiguous naming. also, generally people will also put in a prefix denoting the function of rest of the connected system. ie. you have a tarduiny connected to a shift register. your nets would be labelled "reg_din, reg_clk, etc". by that you know the net will connect from the mcu to the shift register. also all pcb editors have a "highlight net" shortcut which will show exactly where your shit connects. so it doesnt really matter in the end

[Anonymous No.2739871]

>>2739834
Digikey charges slightly over actual shipping label price (it is shipping and handling, after all), it's the component markup that they make their money in.

As a hobbyist, you can try getting your parts from ebay (domestic sellers only), or sites like Tayda Electronics (Thailand) and Jameco (US). AllElectronics also has some neat stuff, but they take a hefty margin themselves.

Personally, for specialist or high-importance parts, I order them from Digikey, but for everything else I order from LCSC because the price is just unbeatable, and less risk of fake parts compared to aliexpress/chinese ebay sellers.

[Anonymous No.2739872]

>>2739871
broooo another one bites the dust. sad.

[Anonymous No.2739880]

>>2739865
>My government hates me and I don't care if me sending money to china hurts our economy
Guess you're right. As fucked as things are It's absurd worrying about these things at this point.
If there is some way to salvage anything of this cesspit, someday we will have out own semiconductor plants again. I'm sure.

[Anonymous No.2739883]

>>2739880
>someday we will have out own semiconductor plants again. I'm sure.
That isn't going to happen unless we unleash hell on environazis and the people pushing globalism/climate shit, and start putting politicians in prison for the rest of their worthless lives.

[Anonymous No.2739892]

>>2739834
>or does this also just get manufactured in china?
Anon, all the largest semiconductor manufacturing operations are in china. No matter how you slice it you are buying from the chinks. You might as well cut out the middleman and enjoy better prices while you're at it. Go on ali, find a shop that has been open for a long time and stocks lots of different parts and order from there.
You might still want to order from big shops when you need rare chips or stuff with mission critical specs. Some of the stuff the chinks sell on ali is binned as out of spec, which is part of the reason why they go for so cheap, but for hobbyist use it doesn't really matter if a mosfet is 0.1R RDSon instead of 0.06R as the datasheet says.

[Anonymous No.2739895]

>>2739834
PT2399 Delay
>from china: $0.50
>from USA: $6.00
PN2222 BJT
>from china: $0.02
>from USA: $0.30
don't even get me started on knobs and MC's. do you know what the retail price of a fucking arduino is out here?

[Anonymous No.2739900]

>>2739895
But Anon, we have to shut down all industry in the west so the salt marsh mouse doesn't go extinct (aka China)! You must be a NAZI Trump supporter with that kind of attitude.

[Anonymous No.2739963]

What creates torque in the motor, the Lorentz force, or the attraction / repulsion of the rotor and the stator magnetic fields (essentially two magnets), or is it one and the same thing? If I had two permanent magnets, I could also create a "motor" by moving one around the other. There's surely no Lorentz force involved in this case.

[Anonymous No.2739966]

>>2739865
I'd like to walk into that store and buy a single 0402 capacitor.

[Anonymous No.2739967]

>>2739871
Yes but they charge more for handling than the average massage parlor.

[Anonymous No.2739971]

>>2739900
Are you implying that if manufacturing returns here we will enjoy China tier prices?

[Anonymous No.2739975]

>>2739971
That's exactly what I'm implying. We'll use slave labor border jumpers and BLM/trantifa criminals to work in unhealthy conditions for 90 hours a week, who spend their off time sleeping in chicken coops while we charge hostile foreign nations a premium and enjoy low, low domestic prices for ourselves and our allies. lmao

[Anonymous No.2739982]

>>2739895
You really can't trust the components from sites like Aliexpress. The chips are usually a lower quality knockoff of a design owned by an American company, or at worse some random garbage with a new label lasered onto it. You use digikey because it's an authorized distributor so you don't have to worry about that shit.

[Anonymous No.2739984]

>>2739982
I only buy big capacitors on Ali because they are very expensive otherwise.

[Anonymous No.2739985]

>>2739984
>very expensive otherwise
Yes.

[Anonymous No.2739988]

>>2739985
that's an exaggeration. i bought some 10000uF caps and they are OK for my needs. i just experiment with transformers. nothing long lasting or mission critical.

[Anonymous No.2740007]

>>2739971
>>2739975
> China tier prices with local manufacturing.

That won’t happen. I live about 12 blocks from a huge plastic injection molding plant. They will sell me (or anyone else) a certain plumbing part for 23 cents. The local home depot sells the same chinese-made part for $5.88.
Home depot does, from time-to-time, source local stuff, but the price will be the same.

Most of the cost of items and services in the west are hoards of private capital, MBA and marketing grads that eventually invade companies and spend 100% of their time just trying to scam their own customers. They will kill the company before lowering the price. They will spend extra money and go into debt to buy back and literally burn unsold inventory rather than let it go cheaply.

[Anonymous No.2740011]

>>2740007
If multinational corporations didn't get tax breaks and other special deals (offshoring and outsourcing), then they'd need to compete with small business who can deliver an equal or superior product at a lower price. The other problem is labor unions (heavily communist political leanings), whose goal is to destroy the west by filling the labor market with highly paid low-quality workers through extortion so China can take over the world. In short, there are certain domestic enemies that need to be put to rest before anything happens in our favor.
It's funny how the same corps can go on a climate crusade for the home audience while their manufacturing base in the east pumps out garbage 24/7/365. People, especially young people, are fucking retards, and nobody has the balls to admit it.

[Anonymous No.2740020]

>>2740007
>a 20c part for $6
that is depressing. so for a local american business 20c is enough to stay profitable and everything on top of it is the middlman's markup that they have no part of? however i tried sourcing some toroidal cores / laminations locally (well on the web but from domestic suppliers) and it is still very expensive, unless you buy wholesale.

[Anonymous No.2740022]

>>2740020
It's also a reflection of the value of the USD.
>Gold is up!
No, the dollar is down.

[Anonymous No.2740028]

>60w iron I have is anemic as fuck
>want something more powerful but the current iron is already big and hard to use, especially for smd stuff
I could go for an 80w iron but I'm worried I'd be overloading my station, as it's for a 40w iron and I'm already pushing it with my 60w iron.
Maybe 2 irons? 40w for small stuff and have the 80w big boy uncontrolled for bigger stuff.

[Anonymous No.2740030]

>>2740028
Buy or build a PCB preheater.

[Anonymous No.2740039]

>>2740020
> toroidal cores are expensive
The west cannot make ferrite or silicon steel objects cheaply because over decades all the suppliers of the raw materials are in china too, and china has a veritable monopoly on rare earths for magnetics.

One thing I forgot to tell you was that I live in an oil-rich state, so the raw materials for plastic are readily available here. But, I ended up buying the $5.88 for the ABS fitting from home depot. It costs more than $10 shipping for a few blocks of distance. My asphalt shingle roof (which is paper, tar, and little stones) for 1000 sq ft simple roof with two slopes cost over $16,000. Tar is a literal by-product of the oil refinery process.

Shipping costs from china are all paid for by fellow US taxpayers already. If you’re not buying things from china, you’re loosing money since your tax dollars already paid for the shipping.

It’s actually cheaper to buy some things here rather than in china, since chinese manufacturers get a 17% rebate on everything they export from the chinese government.

[Anonymous No.2740050]

>>2739834
>Do you guys feel guilty for giving the chinks so much money?

I mean, kind of, but what the fuck am I supposed to do? A lot of the things I buy I literally cannot justify at the 6-10x markup for an "equivalent" made in the US.

It's not even just electronics. I can go through my eBay history and it's just loaded with stuff that's so much cheaper for equivalent or similar performance than US-made stuff that there's no way I'd even be buying it if I couldn't get it from China. Carbide inserts, holders for same, pressure washer nozzle, scaffold casters, rotary welding table, lathe chuck, bearing balls, key stock, brake cable housings...just loads of stuff, it's ridiculous. Even a lot of the stuff that's shipping form the US is clearly just the same imported stuff at anywhere between 50% and 300% markup. Shit's ridiculous.

[Anonymous No.2740062]

>>2740039
>My asphalt shingle roof (which is paper, tar, and little stones) for 1000 sq ft simple roof with two slopes cost over $16,000.
That's depressing. I just checked and I had two roofs replaced in 2012 and 2017 and both were comparable in size, also simple two slopes and it cost about 12k in both cases. Sounds like zero inflation. And now the roof prices are the through the roof. But I guess it is consistent with the insane levels of inflation we have been dealing with lately.

[Anonymous No.2740080]

>>2739826
>the cap gets charged while the voltage is high and will help power the load while the voltage is low
That's a parallel cap. We're talking about a series cap, as in this image: >>2739671.

>>2739828
Cool stuff.

>>2739834
>so I figure it only makes sense for larger order
If you can't find $50 worth of shit you need to buy on DigiKey, you're doing something wrong. Make a list of things as you go, and when it gets long enough to get free shipping, pull the trigger. Should only take a month or two. They even sell consumables, a good roll of solder will more than reach that threshold.

Hobby-friendly vendors are either local fucks who charge over 5 times the price, or aliexpress/ebay chink sellers who sell rebadged bullshit. I got fake TL072s once, don't forget the ever-present TL431 that's actually a TL432. Never again.

>>2739963
Generally it's explained as the torque between a magnetic moment and a magnetic field, and yes you can rotate a magnet by spinning another magnet around it. The normal Lorentz force equation (excluding electric field) is |F| = q*v*B, but for a coil-based motor I often see |F| = I*L*B (ignore the lack of a cross product). I guess if the bulk charge multiplied by velocity within a wire is equal to the length of the wire multiplied by the average current then they're the same thing. In this case I guess it's an equivalent.

>>2739982
I think it's fine to buy chink-branded parts where it doesn't really matter. Like SMD passives, small signal transistors, even general purpose op-amps. But for large MLCCs I'm going Samsung or Murata.

>>2740028
Aixun T3A

[Anonymous No.2740099]

>>2740062
Asphalt shingles are trash which makes it worse. OTOH my 1965 home has a roof of reused heavy galvanized steel that probably dates to before WWII and will be good for a century if periodically coated. My Galvalume steel building bought in 1996 is in great shape though if I do another I'll buy a bucket of flanged head stainless bolts and washers for cosmetic reasons.

Standing seam high quality galvanized roofing will be my choice when I reroof my rental which I already roofed in 1995. Asphalt shingles are nasty delicate flammable garbage.

[Anonymous No.2740145]

>>2740080
>|F| = I*L*B
Yes that's essentially the Lorentz force on a macroscopic level: instead of acting on indvidiual charges it acts on the wire. That's why if a piece of wire is put in a magnetic filed and current runs through it, it will move due to the Lorentz force. But what bothers me is it is just called THE magnetic force (excluding the E field) as if there are no other types of magnetic forces. But clearly if you have a permanent magnet that attracts another magnet, there is a "force" between them. Which quickly leads to a rabbit hole of magnetic moments, quantum spin, etc. And I am lost.

[Anonymous No.2740152]

>>2740145
What's all this physics shit doing on an underwater greased pole climbing board?

[Anonymous No.2740154]

>>2740152
/sci/ usually ignores questions like this. But this is border line physics and EE. Everything that we do in /ohm/ boils down to some kind of subatomic physics... Such is life.

[Anonymous No.2740159]

>>2740145
Permanent magnets are best replaced with a solenoid when constructing a qualitative model of a magnetic system.

But see here:
https://en.wikipedia.org/wiki/Magnetic_moment#Effects_of_an_external_magnetic_field
That's not mentioning the Lorentz force at all, it looks more derived from Maxwell's equations but they aren't mentioned either. You technically can derive Lorentz force from Maxwell's equations, so regardless of where they come from I think it's the same force just in different contexts.

[Anonymous No.2740160]

>>2740154
Let's talk about chemistry instead. What's your favorite narcotic?

[Anonymous No.2740162]

>>2740159
Yes, there's mutual dependency between Lorenz force, Maxwell's equations, and also Faraday's law. For example, the generator effect also follows from the Lorentz force by rearranging and getting E=B x v L aka motional emf. OTOH Faraday's law is E = -dФ/dt which covers both motional emf and transformer emf. Everything is interconnected. It all makes and I feel satisfied for a while but then it starts bugging me again. There are some deep secrets hidden there somewhere. I could never understand the displacement current.

>>2740160
weed and weed only. How do you think I come up with questions like this?

[Anonymous No.2740163]

>>2740162
>How do you think I come up with questions like this?
Why do you think I asked? I learned it by watching you, alright?!
FWIW, weed isn't a narcotic except to feds.

[Anonymous No.2740165]

For the kids:
https://www.youtube.com/watch?v=Uz9LQvn_QUY
https://www.youtube.com/watch?v=3FtNm9CgA6U
These two commercials were sponsored by the US National Drug Dealers Guild, and are credited with creating more drug users than anything the US government has ever done prior with the exception of D.A.R.E. lmao

[Anonymous No.2740167]

>>2739812
Wrong
>>2739821
Right
>>2739826
Wrong.

Okay, so the tegaki guy was right again; once the capacitor charges up, the rectifiers block any discharge so you’ll eventually (in less than a second) get diode leakage current through that — which is sweet bugger all… like nAs and mVs.

[Anonymous No.2740171]

I'm making a GUI using DVI from an FPGA so that i can easily debug my projects that already use FPGAs. The plan is to hook an HDMI connector to some projects of mine so I can have long term debugging/logging embedded in them, I'd just need to come and plug a small screen in to look at what happened for the past few monthes or so. So far everything is great and i can easily print whatever i want to the screen, the problem is that i have no clue on how to easily program a GUI, especially in FPGA.
I'm using the internal RAM to hold the graphical data (not big yuge , 240*135 px) but as far as making a GUI "easily" modifiable i'm completely stuck.

for context, if i were to make a simple GUI in C (writing a single static character to stay simple) i'd have to create a function print(char c, int x, int y , int RGB) and :
- make a LUT of what each character represent in pixels (terminal characters are 5*8 i think ?)
- Transform my input into pixels position using the LUT and x y positions
- write the RGB value into VRAM at the addresses positions found previously
Now the fact that C is sequential make that task rather easy : once a step is over the next begin. if i want to write a string, i just need to loop etc.

Doing so in an FPGA means i'd have to make a state machine which is okay. Problem is that if i want to make a lot of different GUI elements the amount of state increase drastically. while the previous example takes like 6 steps total (without actually outputting the image) writing a second character would make it 12 steps that i'd have to manually write. So, is there a standard on how to do that kind of crap ? Recursion and abstraction is obviously possible, since microcontrollers are synthetisables. But is there a generalized way to do it or do i just have to basically emulate some shitty ass CPU and go through instructions one by one like some whackass diy 6502 ?

(yes, using a high-ish end µC would solve most of my problems. suck it sequential fags.)

[Anonymous No.2740172]

So, how important is it for me to learn calculus and really master the math for an EE I'd all I want to do is repair electronics?

[Anonymous No.2740179]

>>2740172
Depends on what you want to repair. if you don't know shit about the theory then you'll have no way to know what's wrong "at a first glance" and you'll be stuck after checking the usual suspects (blown caps etc.).

I personally don't think knowing the math is actually useful (you barely never do "hard" math even when designing) , but having to study a lot surely helped me retain knowledge even if after a while i ditched the mathematical notions behind it, and I think learning a lot about EE without any context will be more akin to learning magic than science. Some things you might have to repair such as oscillators, filters (or even stubs if you're doing RF) look super hard but are quite simple when abstracted, but if you don't know shit about them all you'll find online are weird math runes.

[Anonymous No.2740180]

>>2740172
zero
electronics repair and EE have virtually nothing in common

[Anonymous No.2740188]

>>2740179
>>2740180
I've been repairing electronics as a hobby and professionally as a tech for 12 years. Im going back for my EE degree because I'm seemingly blocked out of a couple different paths without a degree so figured I might as well go back for a degree, particularly with my employer paying for it. Figured I'd go for EE because I like working on electronics. Just a bit nervous because the math is kind of buttfucking me at the moment.

[Anonymous No.2740198]

>>2740188
I was in the same boat and even had to retake a year which was kinda shameful since i was in my late twenties at the time.
Some teachers are proud of failing students, especially the ones dealing with electromagnetism or quantum effects if you're doing transistor level stuff.

Other than that, knowing basic maths, derivation, integration, basic circuit theory etc. is a must. Laplace transforms can look hard at a glance but it's really easy if you get it. If you have to go through Control systems they'll probably teach you the cauchy and jordan stuff which is a pain and is basically abstracted later on. Some teachers will force you to learn bullshit like Taylor series to get perfect fourrier series since they are gay and hate approximations. I'd say fuck them but saddly they're the one grading you.

Honestly it was really enriching experience but I got really depressed in uni because the teachers were absolute retards and would refuse to see me as a 30 yo adult and were instead treating me as teenager straight out of high school, which was especially hurtful when they told me i'd have to retake a year because I was a literal five thousandth off the minimum acceptable grade.
I think my situation was a bit different though since i managed to get a scholarship : if your employer pays for your classes and you continue to work for them then from my experience the classes are way easier and the teacher are no-nonsense and very efficient / grounded.

[Anonymous No.2740213]

>>2740011
>If multinational corporations didn't get tax breaks and other special deals (offshoring and outsourcing), then they'd need to compete with small business who can deliver an equal or superior product at a lower price.
you should have stopped here
>The other problem is labor unions
no

[Anonymous No.2740215]

how do I work on personal projects on company time without my employer trying to steal my project

[Anonymous No.2740216]

>>2740215
By lying about it. Yes that's the only way.
If you can become stealth successful enough you can survive a lawsuit and then you don't have to hide it anymore.

[Anonymous No.2740256]

>>2740213
> it’s not the unions
a lot of things are 90% automated in china, just like in the US, the workers themselves are a cost decreasing in significance ever year.

[Anonymous No.2740265]

>>2740256
Automation is widely a meme. I encourage you to actually research the topic, it's amazing how little automation can do to this day.

[Anonymous No.2740302]

>>2740167
The only reason there's current at all is the cap isn't fully charged, due to the exponential nature of the diodes. The simulation will eventually reach a steady-state of zero current. In real life there will be a small amount of leakage current through the diodes' junctions and an even smaller amount of leakage current through the diodes' equivalent parallel capacitance.

>>2740171
More of an /mcg/ question.

>>2740213
>no
Runaway unions are the reason there's no longer any more car manufacturing in Australia, among other places. If the unions took a page out of the Scandinavian book they'd be a bit more forward thinking and attempt to actually work with the industries, instead of milking them dry in the short term.

>>2740265
Automation matters for very low-cost stuff, like the soldering of PCBs in cheap goods. Because that's what allows you to perform tasks that simply aren't worth what people want to get paid.
t. once had a job tying wires into knots and putting them in snap-lock bags for a full day

[Anonymous No.2740314]

>>2740080
>the ever-present TL431 that's actually a TL432
>"OMG is that an additional 10mV of voltage drift? Garbage. Absolutely unusable. How dare they sell stuff like this!"

[Anonymous No.2740320]

>>2740314
that's not the main difference

[Anonymous No.2740323]

>>2740314
>>2740320
fyi i've heard of at least three instances where sot-23 tl431s sold on alibay have had the tl432 pinout, even though the marking on the part literally says "431".

[Anonymous No.2740324]

>>2740320
>solder it upside down
there. was that so hard?

[Anonymous No.2740327]

>>2740320
So you are too retarded to see which one is which and connect it the right way around.

[Anonymous No.2740329]

What did he mean by that?

[Anonymous No.2740338]

>>2740329
stop wasting your time on meme software

[Anonymous No.2740341]

>>2740329
you're trying to name the same net two different things

[Anonymous No.2740342]

If I have two halves of an enclosure, and each are electrically connected to ground, but do not have a conductive joint where they meet, is the shielding effectiveness like 99% of what it could be, or do the waves wrap around the object until they find a gap?

[Anonymous No.2740344]

>>2738353
Hot plate or oven

[Anonymous No.2740345]

>>2740327
>So you are too retarded to see which one is which and connect it the right way around
It's labelled as a TL431, see >>2740323. I don't want to have to be soldering each and every chip into a test circuit to figure out if I got scammed or not.

>>2740342
Depends on what you're shielding from.
Magnetic fields will be blocked by induction inside conductive materials, and by permeability in highly permeable materials, regardless of whether there's an electrical connection. Some magnetic field may leak through the gaps if there's a shorter path there for it, but it shouldn't be significant in most cases.
But electric fields will just pull an unshielded metal enclosure to their potential, so to protect against electric fields you want to not only connect your case halves together, but ground them all with respect to your circuit as well. Drilling and tapping holes for ground wires on eye terminals is the way to go here, though spring-loaded contacts from the PCB work well too.
It's not like there isn't some crossover between the fields, and radio waves consist of both of these, but it's roughly correct.

>>2740344
Do you ever plan on soldering boards that have components on more than one side?

[Anonymous No.2740375]

>>2740344
I'm partial to ovens.

[Anonymous No.2740383]

>>2740302
>Automation matters for very low-cost stuff, like the soldering of PCBs in cheap goods.
Yes, but to some extent it depends what you mean by automation at this level.

[Anonymous No.2740385]

I work at a food plant and it's highly automated
and we're always finding new ways to reduce head count. Under the guise of reducing repetitive task injuries in workers ofc.

[Anonymous No.2740387]

>>2740385
What I'm getting at is that while you can automate food transformation, food production can barely be automated at this point, and only trash lowest-end foods can be produced with automated facilities. You won't see even automated mcd burgers at a full scale until 2050 if that, let alone real restaurant-grade foods.
It's the same for e.g. utensils. Good knives still need to be forged or machined and cannot be automated, the mass produced stuff is trash quality only.
Similarly it's impossible to automate wool clothes at all.
Also, even among the items stated above as being automatable, that only applies to a tiny fraction of them.

[Anonymous No.2740407]

They should start automating HR out of existence.

[Anonymous No.2740413]

>>2740387
we make cheese and it's highly automated
no human hand touches it at any stage

[Anonymous No.2740415]

>>2740407
this but unironically
nothing of value would be lost

[Anonymous No.2740443]

>>2739511
>I wonder if that’s what PCB manufacturers use to make plated-through holes.
They use electroplating, first they dip them into palladium solution, this somehow enables copper to grab onto fiberglass, and then they plate more copper onto holes.
It's not a secret.

[Anonymous No.2740444]

>>2740387
>only trash lowest-end foods can be produced with automated facilities

check this video.
see how wrong you are.
https://www.youtube.com/watch?v=Ckhf6WfXRI8

[Anonymous No.2740445]

>>2740443
It’s hard to believe that with the price of palladium nowadays.

[Anonymous No.2740446]

>>2740407
It’s called “talent management” now.

[Anonymous No.2740447]

>>2740446
It should be called "talent repellent" or "visa rubberstampers".

[Anonymous No.2740482]

Noob here: Does this kind of battery already have a protection circuit built in?
And is this SM-2P plug compatible with simple 2-pin jst connectors?

[Anonymous No.2740485]

>>2740482
no. where do you see room for circuit protection.

[Anonymous No.2740490]

is it a bad idea to use JLC's mystery chink oscillators for a microcontroller's clock signal? what about for an RF IC?

[Anonymous No.2740506]

>>2740482
>>2740485
Just to double-check. So in the reviews I saw pic related. It seems, that there is a overcharging-protection built into the USB type A part, correct?
So if the cell itself is not protected, I have to use the mentioned dongle or something with a S-8205A-IC to not overcharge it, right?
Finally: if I use the charged cell in my application, is it basically guesswork, how discharged it is? Except, if its voltage drops below the supply-minimum of my microcontroller?

[Anonymous No.2740518]

>>2740506
>overcharging-protection built into the USB type A part, correct?

so you're hoping 1 of the 40 people on this thread will recognize that mystery charger, and know enough about it to answer questions.
how about you google the name/model/part number.
maybe find a manual, or some amazon reviews.
(my initial reaction is: dont plug a 3.7V battery into a 5V USB thing unless you are super-duper sure you can.)

[Anonymous No.2740533]

>>2740518
>so you're hoping 1 of the 40 people on this thread will recognize that mystery charger, and know enough about it to answer questions.
fair enough. I might just order them and check it myself. cheers

[Anonymous No.2740534]

I have a small 500W hot plate rated at 220V. Is there a convenient way to get this thing working in a country with 110V mains power or should I give up on that? Pic related, I have the EU version.

[Anonymous No.2740541]

>>2740506
>>2740533
That's only a charger, Anon. It's built into the cable. The over-discharge protection is meant to be on the PCB of the RC vehicle, and the short-circuit/overcurrent protection could be a simple metal disc under the battery anode that flexes outward and breaks the connection (protected vs. unprotected cell), or it might not have those protections at all.

[Anonymous No.2740543]

>>2740534
>Is there a convenient way to get this thing working in a country with 110V
If you're okay with only getting like 120W of power then you can cut the plug off and replace it. These things are just glorified resistors so they're not that fussy about voltage.
If you want the full 500w you won't be getting that without a transformer.

[Anonymous No.2740554]

>>2740534
>a convenient way
step-up transformer

[Anonymous No.2740555]

>>2740534
>country with 110V mains power

a transformer like this is gonna cost you $40 minimum.
a thrift store hot plate will cost less than $10.
but it wont be as kawaii as yours.

[Anonymous No.2740593]

>>2740555
I thought those things went out of fashion a century ago

[Anonymous No.2740598]

>>2740534
Good news! Now it’s a 250 watt hot plate and it will probably last for five forevers instead of just one forever.

[Anonymous No.2740600]

>>2740490
What microcontroller doesn’t have a built-in oscillator. Even some of the big-ass DIP µCs had them in the 70s.

[Anonymous No.2740607]

>>2739834
I buy my stuff locally (from Spain). It already gets quite expensive at times but at the end of the day I pay a lot more less than bringing stuff from Digikey/Mouser.

The only thing I bought from China were some PCBs from PCBWay.

[Anonymous No.2740618]

>>2740534
If you're in North America, you probably already have 240V/208V power in your home. You can make an adapter for a dryer outlet, or any other 240V appliance outlet.
That said, the cost and hassle is probably more than just getting the right hotplate.

[Anonymous No.2740620]

>>2740482
There is likely no cell protection in those. Cells with protection have a small wire or nickel strip you can usually feel going down the length inside the shrink-wrap.

>>2740506
> if the cell itself is not protected, I have to use the mentioned dongle
Even if the cell had overvoltage and overcurrent protection, you wouldn't be able to avoid using a CC/CV charging circuit. That protection simply cuts out if an impermissible source is connected, it will not regulate a charging current and voltage.
>S-8205A-IC
That's the protection circuit, not the charge circuit. The charge circuit would be something like a TP4056. You don't need a protection circuit when charging through a properly designed charger chip like this, the protection circuit is mainly for when you're charging it off an unregulated supply with limited output current (e.g. a small solar panel), or more commonly for preventing the cell being damaged when installed into a load that doesn't care about cell voltage (e.g. a flashlight).

Typically a dedicated lithium ion USB charger dongle will say 3.7V or 4.2V output on it, and these will be fine to connect if you get the polarity and connector correct. If it says some other voltage, either it's designed for a different chemistry (e.g. 4.8V NiMH) or it's designed for multiple series lithium cells (e.g. 11.1V). 3.6V is an ambiguous state that could be either NiMH or lithium ion, but usually they say the chemistry on them. Worst case you can just disassemble it and read the IC name.

t. sell rc vehicles at an electronics shop

>>2740534
It could be that there's a way of rewiring two elements in series or in parallel on the inside of it.

>>2740555
>$40 minimum
lmao we sell these for like $300

>>2740598
Actually it's 125W if we assume minimal tempco.

[Anonymous No.2740665]

>two mystery items on LCSC
>made by LCSC
>no datasheet or image
gonna add them to my cart, wonder what they are

[Anonymous No.2740668]

>>2740620
>lmao we sell these for like $300

yikes at them Yahudi christ-killer prices.

[Anonymous No.2740669]

>>2740618
>You can make an adapter for a dryer outlet

this goy has just reminded me that it's pretty easy to get 240V from two 120V sockets in the kitchen.
you just need 2 extension cords to access the live wires from 2 separate sockets. like in the pic.
some kitchen sockets are split-phase, meaning you can get 240V from just that one socket.

[Anonymous No.2740671]

>>2740618
>You can make an adapter for a dryer outlet
You can, provided you find 2 outlets that are on different phases. But you shouldn't, because a drier outlet is 60 amps and 2 outlets are going to proved 30 amps if you are lucky and nothing else is on the circuit.

[Anonymous No.2740682]

>>2740413
Sure. If you make """cheese""" and not cheese.

[Anonymous No.2740684]

>>2740444
>check this faked advertisement video for a thing that doesn't exist
lol
lmao even
literally proving my point anyway: it wouldn't "shock the world" if automation could already handle it.

[Anonymous No.2740697]

>>2740482
>Noob here: Does this kind of battery already have a protection circuit built in?
Probably not.
>>2740445
Maybe not all places use palladium process, I think you can get away with graphite or idk.
In my PCB designs... I dont design shit multi-layer if I know I'd have to etch it. 0 ohm links exist for a reason

[Anonymous No.2740710]

>>2739834
>Do you guys feel guilty for giving the chinks so much money?
No. RS won't sell lithium batteries or fluxes to my country. Digikey doesn't send to my country. Mouser wants 30 bucks for shipping.
Zheng is a bastard, but he does it for reasonable amount of money.
I hate chinks, but there is no alternative, white people aren't into selling, and jews are occupied with their agenda instead of trading.
What is really fucked up is that chinks somehow get foreign made shit you can't buy anywhere, except fucking china. Like Intel CPUs for example, in BGA package. Or idk, batteries.

As soon as somebody else starts providing similar service to chinks, they would win. Why can't pajeets or vietnamese do it?
Other thing is that I can buy shit on aliexpress that just doesn't exist in digikey or whatever.

[Anonymous No.2740806]

>>2740445
The palladium is just a catalyst for electroless copper plating. It doesn't have to form a full metallic coating, as such a very small amount of it is used.

[Anonymous No.2740815]

>>2740710
>Mouser wants 30 bucks for shipping
I just bought 64 different items for $350 from LCSC, and shipping was like 10% of that, which is fine considering the low prices of everything else.

also holy shit i just realised one of the cells in these lipos i haven't used yet is sitting at 1.8v

[Anonymous No.2740851]

>>2740671
My stove has an outlet already on it, pretty much directly connected to one side of the 80 A 220 V feed.

[Anonymous No.2740897]

>>2740815
>also holy shit i just realised one of the cells in these lipos i haven't used yet is sitting at 1.8v
it will be fine

[Anonymous No.2740941]

I'm trying to use altium to make a simple to-8 breakout board. Does altium really not have built in footprints? The footprint wizard doesn't even have through-hole components, let alone to-8 cans as far as I can tell.
I'm used to KiCad's workflow. There's no way I can believe the FOSS software has more capability than the expensive proprietary software

[Anonymous No.2741056]

>>2740710
>What is really fucked up is that chinks somehow get foreign made shit you can't buy anywhere, except fucking china
The best part is that you can get absurd stuff that no consumer would otherwise be able to own. Like, a 100W output laser diode array is not just for sale but it's only like a couple hundred bucks, the driver is included for another 80$ or so. It's not dirt cheap but cheap enough that you could afford one.
Also cheap enough that someone might just shoot up a school with it.

[Anonymous No.2741064]

>>2741056
>Also cheap enough that someone might just shoot up a school with it.
Hm. Which one is better, IR or blue?
For marking pork of course, like brandname so it is cool and shit

[Anonymous No.2741071]

>>2741064
IR for sure.

[Anonymous No.2741084]

hey guys I want to make an electromagnet
How do I decide what gauge of wire to use?

[Anonymous No.2741122]

>>2741084
use the Sugondis formula

[Anonymous No.2741129]

>>2741056
Is it actually 100w?

[Anonymous No.2741138]

>>2741129
no, there are no real 100W diode lasers

[Anonymous No.2741153]

>>2740941
Maybe you need to download extra footprint packs, there's a few easily available for KiCAD but no clue about Altium.
Any reason to use it other than "to learn what my future job might use"?
>inb4 autorouting

>>2741084
Depends on what your limiting factor is. Usually you're constrained by volume, in which case the total length of wire you use is determined by that wire's diameter and the size of the area you have to wrap it in (assume square packing). The thicker the wire, the lower the resistance, but the fewer turns you'll be able to get. If this electromagnet is going to be used with continuous DC power into it, the maximum current will be limited by power dissipation. We can make the assumption that the exterior surface area of a 1/4W resistor is ~1 square centimetre, so you can follow that guideline and should get in the ballpark for the geometry of the shape you're winding it for. Now the heat P produced in watts is given by P = V*I = V^2/R, and the resistance R is determined by the thickness and length of the wire, look it up in the awg wikipedia page. The voltage should be for whatever power source is most convenient to use there. You don't really want to have to use DC-DC converters if you don't have to. The pull force of the solenoid is roughly proportional to the current multiplied by the number of turns of wire (amp turns), note that this cancels out with respect to voltage if volume is kept constant; 3ccs of winding volume will produce the same force for the same amount of heat dissipated regardless if it's 2Ω at 10V or 0.2Ω turns at 1V. I'd do the calculations to see how close 24awg would be, then trial-and-error your way there by changing the wire size until it suits you. Do it in a spreadsheet so you can propagate the formula to compare and contrast multiple options. Thicker wires are more difficult to bend, while thinner wires need more windings to fill the space.

There may be online calculators for this, but I prefer to do it myself.

[Anonymous No.2741155]

>>2741138
please understand laser is 100w electrical it only 10% efficient so only 10 of those watts optical do the needful rate 5 stars please

[Anonymous No.2741161]

EE thread on /pol/
>>>/pol/454733488

[Anonymous No.2741170]

>>2741056
I got a 1200 W IR gun at lowes for $23.
I use it to shrink tubing.
Despite being 10 times more powerful, don’t think it’s taking out an entire battalion for some reason.

[Anonymous No.2741175]

>>2741161
b8 thread != ee thread

[Anonymous No.2741288]

>>2741161
Don't even bother linking these shitty threads. Even the ones on /sci/ are barely readable.

>>2741170
If that 1200W of heat was focused on a square millimetre or less, then it could probably burn through your hand in a few seconds.

[Anonymous No.2741290]

>>2741129
Considering that the power consumption is in the range of 300-350W I'm inclined to say that yes, it is 100W of optical output, or at least close enough.
If you want to know more, a youtuber did a video on one of these.
https://www.youtube.com/watch?v=W6FbUiiwutQ

>>2741170
That's not a laser, retard. Also the point never was to kill people with it. In Minecraft, of course.

[Anonymous No.2741294]

>>2741288
Just get gallium lenses which can focus the IR. It’s also 99.9 efficient, so it’s actually 100 times more powerful than the 10% efficient laser, not just 10 times.

[Anonymous No.2741300]

>>2741294
>spherical lenses with incoherent light
>getting anywhere near laser intensity
>not deforming from the 12W they'll absorb
I don't think so, especially not at any kind of human shooting range.

> it’s actually 100 times more powerful than the 10% efficient laser
A: the high-power diodes are in the realm of 30% efficient
B: they consume over 300W of power

[Anonymous No.2741325]

I just read on a government website that old batteries that are going to be disposed should have their poles taped off with electrical tape to prevent a fire hazard.
Thoughts? Is this something people actually do?

[Anonymous No.2741331]

>>2738833
Very interesting. I missed the earlier threads, so don't know what the intended use is. With something like this I would record structures like utility poles and wire fences (wind noise?), bridges (traffic noise), trees (in extremely cold weather they can emit cracking sounds), and especially cracking lake ice. Good luck whatever you do.

[Anonymous No.2741332]

Since this thread is fairly slow I'll add some extra information. It's a german website but translated with DeepL it says

>Before disposing of your lithium-ion battery or rechargeable batteries, you should cover the terminals with insulating tape (alternatively: adhesive tape) to prevent a short circuit.

>If the lithium-ion battery is not installed in the device, the battery should be disposed of individually at the appropriate collection points.

[Anonymous No.2741334]

>>2741331
>don't know what the intended use is. With something like this I would record structures like utility poles and wire fences (wind noise?), bridges (traffic noise), [snip]
Bingo, it's intended for field recordists, sound designers, and musicians to capture normally "invisible" sounds, or sounds in noisy environments (because it doesn't pick up sound waves in air, if you want to record something like the beeping of a cross walk signal, you can just press it to it and get a very clean recording). When it warms up outside I want to find an anthill and see if I can hear ants moving underground at max gain (51x or 34dB)
>Good luck whatever you do.
Thanks!

[Anonymous No.2741335]

>>2741325
At my former workplace we were required to tape the ends of every battery recycled or disposed of, regardless of type. Maybe just the policy of the local safety officers, IDK. (Large multinational corp.)

[Anonymous No.2741390]

>>2741335
>(Large multinational corp.)
Big Tape has their tentacles everywhere.

[Anonymous No.2741442]

i broke my phone glass, fortunately that only contains the tactile sensor and not the full screen, so i asked for a new one and just went to change it, but when i went to dismount the phone i found that it was difficult to take out the screen connector but i didnt give any importance, but then when i went to replug it i saw one of the pins moving, half out of place, and when i tried to bend it to place it went as picrel
i shouldnt have taken the phone to that maltese shop years ago
how hard is that to change that?, i have done some smt but not this level... how is that conector even called? phone is an xcover 4s
i guess i should go to the local tech shop tomorrow

[Anonymous No.2741443]

>>2741442
It's called a mezzanine connector. The specific part number I don't know.

[Anonymous No.2741454]

>>2741442
>xcover 4s
Maybe Panasonic AXE634124.

[Anonymous No.2741463]

>>2741443
>>2741454
thanks i look into it if the local technician doesnt want to repair it.
I should learn to weld those anyway, i guess, so ill try to find some videos on how to

[Anonymous No.2741464]

>>2741325
It only actually matters if the battery still has charge, it's a preventative measure to prevent it shorting out. If instead the battery was empty, and you added a wire from terminal to termainal to ensure it doesn't accumulate a remnant charge, it should be even safer. Just fully discharging the battery should be safe enough, though it depends on chemistry.

Though ultimately, if a lithium ion cell beneath a metre of landfill goes up, it doesn't really have an impact. The tape isn't going to last forever, but it really doesn't need to.

>>2741442
They're a pain to solder, but not impossible. There's likely videos of people soldering them.

[Anonymous No.2741472]

I'm doing the "Learn by Discovery" book of the "Make.." series. There is this experiment with the 2N222A transistor that its not working for me.

I ran the simulations and it works (because the only video of this exercise that exists shows a previous version).

I can also post a screenshot of how I have it but it isn't much different aside from having a slider switch instead of a pushbutton (I tried two different switch already).

Voltage into the collector sits at 12V when the switch is not pressed but in the base its at 11.6-11.8V and at the emitter is at 4-5V even if the button is not pressed. If pressed, the voltage simply stays solid.

I tried two different 2N2222 models and my multimeter throws 150+ hFE values for both so I don't think they are broken.

[Anonymous No.2741474]

>>2741472
Cont: I doubled checked the resistors. All values are correct. Simulation shows what should be hapening which is not letting anything through until you flip the switch but physically the fact that measuring at the base shows there are also almost 12V puzzles me. I don't know what I'm missing exactly.

[Anonymous No.2741490]

>>2741472
double check the pinout

[Anonymous No.2741517]

>>2741474
>don't know what I'm missing exactly

your LED might be backward, or burnt out.
short it with a wire, and see if voltages become more normaler.

[Anonymous No.2741524]

>>2741472
Pic related. As the lower impedance is on the collector, this circuit will act like a common-collector circuit, which is unusual (and kinda shitty) for turning on an LED. When the button isn't pressed, you should find 11-12V across the switch and across the collector-base junction, and 0V across R1, R2, R3, and D1. When the button is pressed, the voltage across R1 should be about 2V, and the voltage across R3 should be about 7V. Importantly the voltage from base to emitter should be around 0.7V, and the voltage across the LED should be 2-3.5V, depending on colour.

If there is a voltage at the emitter of 4-5V, it means either the transistor is properly turned on, or it's broken and passing current anyhow. If the LED isn't lit up, then it may well be backwards or broken. The short leg should be on the negative rail.

IIRC this is a reason we decided to remove this book from the OP.

[Anonymous No.2741531]

>>2741490
Pinout is correct and I assembled the circuit three times already.

>>2741517
The LED works. Turns on using the multimeter and also with a simple LED-Resistor circuit. Tried different ones too.

>>2741524
I would have to check the voltages of each thing. Aside from that the LED is working properly in a different circuit and with different LEDs the result is the same.

I've been trying to check if the transistors might have been broken using the multimeter resistor test. Supposedly you connect common to base and red to collector and/or emitter and see if there if you get ohm values. This wasn't working at first until I did it backwards with red at base and common on collector and emitter. Is this normal behaviour?

> IIRC this is a reason we decided to remove this book from the OP.
Yeah, sadly I bought a bunch of the books materials and at least there is still some interesting stuff and experiments in the book which I'm planning to do.

[Anonymous No.2741536]

>>2741531
>I would have to check the voltages of each thing
That's the surest way to troubleshoot it. You can either measure voltages across each component, or measure them all with respect to 0V, but I'd do so when the switch is in both positions and write the voltages on a circuit diagram.

It might be that the breadboard connection points aren't reliable enough.

>red at base and common on collector and emitter
>Is this normal behaviour?
Yes it is. Current flows from base to emitter like a diode during normal operation (hence the 0.7V drop), and it similarly flows from base to collector under reverse operation, because an NPN BJT is made of two PN junctions, which are naturally diodes. The transistor only works in one orientation because of the specifics of the dopings, however.

>I bought
libgen

[Anonymous No.2741539]

[Anonymous No.2741542]

>>2741536
>>I bought
>libgen
The materials (ICs, Leds, transistors, diodes, etc), not the book. Although the book came in a humble bundle with a bunch of other books for like 10$ or something. Its the 1st edition and apparently this book is already at #3. No wonder it seemed weird to have a book ask you to buy obsolete parts or stuff from Radioshack as if most stores still have that stuff hanging around.

>It might be that the breadboard connection points aren't reliable enough.
This could be. I'll try in another board and see if something changes and will take the time to check

[Anonymous No.2741618]

>>2741539
why the hell would you put the led on the emitter instead of in series with the collector

[Anonymous No.2741621]

>>2741618
lurk moar noob

[Anonymous No.2741638]

Dave Jones is hilarious. Australians are ridiculous

[Anonymous No.2741644]

>>2741618
You see this topology more in non-inverting buffers,
Sometimes in RTL logic gates (where this originated from, F.M.M.III is an old guy who remembers that shit)
Other high-speed or otherwise special line drivers where capacitance is a concern.
Also, it’s possible it consumes less current in it’s quiescent state or something (depending on how it’s used).

[Anonymous No.2741647]

>>2741644
>RTL logic gates
The logic depth is fundamentally limited. Each time the signal goes in and out a non-inverting logic circuit in this topology, the output voltage drops by 0.7V. I can still understand the use of emitter-followers for analogue and digital applications, but for switching a load like an LED where speed doesn't matter I can only say it's worse than the alternative, and teaches bad practice. That common-emitter amp would also be a pain to bias, you're almost always better off using an emitter resistor with a cap across it.

[Anonymous No.2741712]

>>2741638
Elaborate

[Anonymous No.2741727]

>>2741712
They're just goofy, it's like looking at a cartoon character.

[Anonymous No.2741729]

Making lamps

[Anonymous No.2741771]

>>2741729

shit's gonna get hot enough to melt the hot glue.
gonna need some J-B weld.
or trowel in some 1000°C fireplace mortar.

[Anonymous No.2741774]

>>2741729
>>2741771
How to make a nice house fire.

[Anonymous No.2741845]

Let's say I want to power a sensitive amplifier that operates in the gigahertz. Switching harmonics for an smps decrease at 1/(multiple of fundamental), so if I make the thing switch at ~500 kHz to 1 MHz, by the time we get to the frequencies of the amplifier, the harmonics should be negligible

Tell me why I'm retarded

[Anonymous No.2741874]

>>2741845
Yes, that's one component you have to worry about. Then you also need to consider output impedance of your smps and whole power delivery network - that's the messy part. If your amplifier drives low impedance load current draw combined with high power network impedance could result in additional noise. Proper decoupling is important.

Don't forget that at any point noise from outside can also couple into the power supply. Depending on your target noise levels you'll have to consider all such potential noise sources.

[Anonymous No.2741896]

>>2741729
Is this for growing the magical beanstalk?

[Anonymous No.2741909]

>>2741647
> bad practice, 0.7 volt drop
Probably doesn’t matter at all in LED driver applications especially at Vcs at 9 and 12 v.
It may actually be better to do it this way if all you’ve got is 1 kΩ resistors, which was the obvious design goal.
Not everybody is going to have picrels in all values lying around, but 1 k is something everyone has copious quantities of.

[Anonymous No.2741933]

>>2741909
The voltage drop is only an issue in the context of RTL logic circuits.
I don't see how putting the LED above the BJT instead of below it would change whether or not it would work with 1k resistors. Sure you'd get a bit more base current, but it would be in saturation anyhow.

Also 10k is more common than 1k.

[Anonymous No.2741946]

I wanted to buy a portable induction cooktop.
And I obviously went for my favourite option, aliexpress special.
While ordering, I thought to myself, that shit would be like a welding inverter or something, except secondary coil is replaced by short circuit winding called a pot on top of damn thing.
But then after googling I realized that cheapest cookers use quasi-resonant topology, i.e. one LGBT transistor (with built it diode obv) and coil with capacitor. And now I'm wondering if I did fuck up, because it seems like adjusting power on this kind of topology would be a pain in the ass, compared to the half-bridge where everything is obvious.
https://toshiba.semicon-storage.com/ap-en/semiconductor/knowledge/faq/mosfet_igbt/igbt-013.html
Other thing is that I don't understnad why do chinks put different programs in the shit, like what the fuck soup, stir fry, the fire, etc. modes mean? Why not just put simple power adjustment and temp adjustment feature?

[Anonymous No.2741954]

>>2741946
I think they use a push-pull topology like a ZVS driver, if not a full H-bridge, and that it is a quasi-resonant topology. To modulate power, they could either skip cycles or entirely turn off for a short period. I have a cheap induction hob that switches itself off and on at 0.1Hz to modulate power, and it's fucking awful since things like sauces bubble and splatter vigorously before turning off completely. There's nothing preventing you from switching it on and off at 10Hz at the very least, which would be enough for basically all food use. Skipping cycles should be doable without eating inductive spikes even with a half-bridge, since I doubt there's much energy stored in the coupled inductances that isn't eaten up by the shitty Q factor.

I don't think they can just use a single transistor like a flyback converter.

>like what the fuck soup, stir fry, the fire, etc. modes mean
It's probably just a brainlet abstraction. It may well control average power, but it might also control the modulation frequency, higher frequencies are better for more delicate food items. I'd scour the net for a model that has power adjustment at the very least, and check the reviews for how it handles the modulation.
>temp adjustment
Very difficult to do without a temperature probe inside the pot. Arguably you could measure the resistivity of the magnetic load from the oscillator's changing Q factor, assuming it's a known alloy, but it wouldn't be too accurate. Infrared measurement through the glass is complicated since the emissivity of pots can vary a lot, but it may be doable.
I think you'd be better off with a plug-in external sensor, ideally built into the pan itself. Sous vide with no extra hardware. I'd also like to see a gas production sensor built into saucepan lids, so you can set it to a certain boil rate with feedback.

[Anonymous No.2741956]

>>2741946
My induction burner cycles the power like a regular (“non-inverting”) microwave oven, or even your stove. The frequency it cycles the oscillating coil is around 1 Hz. The oscillations of the coil are definitely in the kHz, I can hear it (or some harmonic) with a small pot and a loose fitting lid.

You’re right, it’s not always easy to change the power level of something due to the voltage, current and frequency. I have a battery charger that has two primaries because it’s easier to switch the mains than it is to switch the high current 12 V to 6 V on the output.

[Anonymous No.2741962]

holy shit my chinky t12 tip just started glowing red hot
hope it was the tip and not the station, but the thermocouple is in series with the element so it may well be the station's power fet

[Anonymous No.2741964]

>>2741954
>I think they use a push-pull topology like a ZVS driver, if not a full H-bridge,
Idk. It probably has just one IGBT transistor (idk, we will see when i get it lol), and I suspect it is similar to toshiba application note I found. (https://toshiba.semicon-storage.com/ap-en/semiconductor/knowledge/faq/mosfet_igbt/igbt-013.html))
>cycling at 0.1Hz
thats awful and disgusting.
>Very difficult to do without a temperature probe inside the pot
You have next best thing, a thermocouple under the glass.
>I'd also like to see a gas production sensor built into saucepan lids, so you can set it to a certain boil rate with feedback.
I want fully programmable cooking cycles like they have in BGA rework stations lol. And thermal couple in the food and in pan, but that's defintely overcomplicated lol.

But then, on photos there is an adjustment pot on the PCB, and I wonder if turning it will change real power. Dunno.

[Anonymous No.2741966]

>>2741964
>is similar to toshiba application note I found
Well that would be easy to adjust, since the on-time of the IGBT can be freely changed.
>thats awful and disgusting
It also has this glass capacitive touch display rather close to the elements, that's really easy to touch with a large pot or pan, accidentally turning it off. And it doesn't work properly if there's any water on it. Just put the controls on a seperate panel for fuck's sake.
>a thermocouple under the glass
There's a lot more delay in that than there is in the operation of the induction hob itself. If you were to rely on it to prevent thermal overshoot, you'd need to limit the heat-up ramp quite severely, at which point you'd have little advantage over a conventional electric hob. My 0.1Hz hob uses thermistors under the pots to give you a warning not to touch the glass, that's it.
>I want fully programmable cooking cycles like they have in BGA rework stations lol
Me too. I may just bite the bullet and get one of those chinky induction hobs, in order to replace the control circuit with my own. No clue how easy it would be to interface with the existing power circuitry though. I've got some 400V+ IGBTs and some nice gate drivers on the way for a seperate project, so there's always another option.
>And thermal couple in the food and in pan
I saw a neat video from Applied Science, where they put a thermal sensor among other things inside a magnetic stir-bar, that communicated wirelessly to the hotplate. Be nice to do it that way, but wireless communication might be a tenuous proposition in the middle of an induction hob element.

>an adjustment pot on the PCB
It may just be to adjust oscillation frequency (only applies if it isn't resonant), thoughI saw one schematic of an H-bridge induction circuit that used a pot for adjustment of the coil current limit.

[Anonymous No.2741973]

>>2741962
ah the mosfet is dead, it's:
tpc8107 p-channel 60v 5.5mΩ 130nC soic-8
think i'll swap it for wires going to an sup53p06 bolted onto the chassis somewhere, either with my old iron or with the somewhat nicer iron at work

[Anonymous No.2742059]

>>2741973
You know you have to clean the years of greasy dust out of the thing, right?
Mosfet probably burned up.

[Anonymous No.2742073]

>>2742059
It’s a SOIC FET with no heat-sink or fan, barely even any thermal vias. The enclosure has no gaps for airflow, so no dust got in there. It’s a chinky T12 station, good thermal design is not a given.

[Anonymous No.2742075]

>>2741954
>switches itself off and on at 0.1Hz to modulate power, and it's fucking awful since things like sauces bubble and splatter
that's fucking hilarious lmao. deltas built to suffer forever

[Anonymous No.2742093]

>>2739053
>What I lack is purpose, an objective, and an idea.

Try making something that helps you do something?

I am in process of slowly adding features to my underwater drone. It went from basic motor control to learning about Arduino PS2 controller interface to FPV camera stuff to antennas to 3d printing, which was another thing in itself. It also expanded to Raspberry Pi and Python coding overall.

Why? I just wanted to check out and sift through the bottom sands of a water park resort beach where a lot of people swim, boat etc. since I'm not able to dive because of health issues, just to see if there's any items there. I like exploring but adventures, not so much :)

[Anonymous No.2742114]

can 4x LiFePO4 batteries be dropped in place of Lead Acid? Will the charging setup work?

2 main things Im considering doing this for are old UPS units with dead lead acid batteries, as well as being able to just plug a 4 cell pack into a car cigarette lighter

[Anonymous No.2742121]

Have a 8mm silicon tube and need to detect when liquid is flowing through
What sensor am I looking for?

[Anonymous No.2742124]

>>2741771
>hot
its not.

[Anonymous No.2742264]

>>2742121
Optisonic 4400 (HT)

[Anonymous No.2742337]

I'm selling a doodad. It needs a USB-C charger included. It can be a quite shitty one, it's just powering a Arduino, but I don't want it to be unsafe. I can buy 20 USB-C chargers from Ali for $10, but will they explode? what's the cheapest UL-listed one-port USB-C wall charger I can buy? I'm new to the world of low-volume cheap parts...

[Anonymous No.2742403]

>>2742114
>can 4x LiFePO4 batteries be dropped in place of Lead Acid
Depends on the load and charger. The maximum current, and overcharge and overdischarge voltage thresholds will all be wrong. Furthermore, the common method of lead-acid charging is just "pulse 14V or more at it", which other chemistries don't take nicely to. I looked into LiFePO4 use for a UPS once before, I found that with all the thresholds and shit being baked into a microcontroller (PIC16F73-I/SP in my case) I'd need to reprogram or replace it, and replicate all the safety programming. While doable, I'd be more comfortable just using its transformer and transistors and relays to make a custom UPS, preferably with someone else's code. I'm not sure to what extent you could modify the charge circuitry, if you reverse engineer it you could probably put a parasitic MCU in there that reads the input and/or output signals that would originally be used for charging (e.g. mosfet control line, voltage feedback, current feedback) and replacing them with its own signals in order to get a desirable charging curve. Then the overdischarge protection could just be a series BMS. I don't think you could just disable the charge circuitry and use an external charger, but I may be wrong.

>plug a 4 cell pack into a car cigarette lighter
You mean to put it in parallel with the car battery? Not without some current limiting.

>>2742121
Will there be liquid inside the tube all the time, or only when it's flowing? If the former, you'll likely need an ultrasonic sensor, though I swear it should be possible to detect fluid flow using electrostatic induction.

>>2742124
based eco-LED modifier

>>2742337
>It needs a USB-C charger included
Why? Don't people already have those? Don't give them junky ones, it's a fucking pain to have a bunch of chargers and not know which ones support fast-charging for which devices. Actual UL listed ones won't be below $15 each I bet. What are you selling?

[Anonymous No.2742442]

>>2742337
>It needs a USB-C charger included
No it doesn't. Most people already have them around, and if they don't, they can get a reputable one for their specific country.
Cheap ass chargers are a fire and shock hazard. You won't be able to beat the local price for a UL-listed one, and if you find one that does, the markings are 99.9% of the time fake.

[Anonymous No.2742444]

Can I get a second opinion on this RF block? Haven't worked with antennas before, or this PN532 chip. Does the connection to the U.FL look right? Something feels off

[Anonymous No.2742449]

>>2742444
Are C3/C4 meant to connect to ground? Because at the moment they're not. Also 220pF seems kinda high for a crystal.
Are you following the datasheet, or an appnote? Appnotes are usually more thorough and explain the extra things to watch out for.

>using an LM317 in this decade
Double check its maximum dropout, if I recall running 5V down to 3.3V is marginal. You'd be better off using an LDO.

[Anonymous No.2742457]

>>2742442
>>2742403
alright yeah I guess I'll leave it out

[Anonymous No.2742471]

>>2742449
Thanks for the input, especially re. Using an LDO. I'm a firmware guy, and a pretty new one at that. Anyways, I've been poking around online for reference schematics (picrel). Not sure about C3/C4... I don't think so. Never done any RF stuff before - this is for fun. 220pf on the crystal was a copy/paste error. Off by a full order of magnitude. Nice eye.

[Anonymous No.2742473]

>>2742449
> lm317 dropout
According to the datasheet, TI wants a ΔV of 3 volts! That’s pretty shocking, I always ensured a 2 V minimum and thought I was being generous for the last few decades.
That’s bullshit. For once, I’ll agree that the old LM317 should be retired.
Half the shit I have uses low-VA transformers and has a lot of voltage sag under any kind of load, like 500 mA, so that’s not very good.
Is there a common industry standard part that replaces it that needs less of a overvoltage?

[Anonymous No.2742482]

>>2742471
>Not sure about C3/C4... I don't think so
Well in the one you just posted, the equivalents C6/C8 are tied to ground, as opposed to just being tied to one another. But that schematic is doing a double-ended RF output, not just a single-ended output. I'd leave a solder jumper footprint from the C3/C4 node to ground at the very least. I assume you can configure whether TX1 and TX2 are in-phase or out-of-phase?

>Never done any RF stuff before - this is for fun
My takeaway for all analogue stuff is to leave plenty of footprints and jumpers for various configurations. Especially considering you get 5+ boards from JLC.

>>2742473
>According to the datasheet, TI wants a ΔV of 3 volts!
Yeah it's pretty bad, though if you look at the dropout vs current or dropout vs temperature graphs you can see it does drop somewhat.
>Is there a common industry standard part that replaces it that needs less of a overvoltage?
The fixed voltage 78xx series, and maybe the AMS1117. The 1117 is only good up to 15V input, but it goes down to low voltages. The 78xx series doesn't have anything lower than 5V by default, but usually I find I never need more than 15V input tolerance for a 3.3V circuit. If I do, there's usually a 12-5V switching/linear regulator I can put the 3.3V regulator on instead.
There's always the option of making a TL431+BJT regulator, with a big enough capacitor the ripple rejection can be really good, even at high frequencies. Since the 431 is a shunt regulator, the input voltage tolerance can be as high as you can find on a BJT, and the dropout voltage can be in the 1V range too, at the expense of a pretty bad quiescent current.

If you need anything more specialised I have a couple of other suggestions:
>HT7333 - a 3.3V regulator with extremely low dropout, for maximising usable voltage from a lithium ion cell
>REF33xx - actually a voltage reference but it's constructed as a pass-regulator, can be used to provide a very stable voltage supply for op-amps

[Anonymous No.2742489]

>>2742482
Yeah. They're definitely meant to be tied to ground - I'm blind. Thanks for that. And yes, I have a feeling my U.FL connection is wrong. I'll have another look at the PN532 datasheet re. phase config, this is all new to me.

[Anonymous No.2742499]

Fixed it! The SOIC MOSFET didn't even have a thermal pad, so now it's got way more heat-sinking than it ever did. Though the RDS_on is 32 times greater now, it's still not going to produce more than a couple of watts of heat, which is fine for a TO-220 clamped to an aluminium chassis. Feels good to be able to fix something without having to buy any extra parts.

Additionally, the tip that got up to glowing temperatures is still working, the plating seems fine even.

[Anonymous No.2742502]

My family has this Montgomery Ward 2443.
It works playing records but only on a specific volume setting, else it only comes out of one speaker.
I've reccaped an old tecktronix o-scope, so I'm not a complete noob, but I can't find schematics, and don't know where to start on something this old besides looking for electrolytic caps and hoping they have specs written on them.
Any tips?

[Anonymous No.2742504]

Just went through every P-channel MOSFET in the KiCAD symbol libraries, and flipped them so the body-diode points upwards. The default orientation caused me to bend a bunch of TO-220 legs once.

[Anonymous No.2742506]

>>2742502
Potentiometers are suspect in old equipment, especially when results are volume-setting dependant. I recommend that you remove the potentiometer from the unit, check what value it says on the side, take it apart, and clean the wipers and resistive elements with some alcohol and a Q-tip. I sprayed some IPA into the funky pots on my oscilloscope the other day even without taking them apart, and that seemed to do the trick for now. If that doesn't work then it likely isn't just caused by gunk inside the pot, so replacing it becomes the only path forwards. With any luck it's a common model, but you can generally replace any pot with any other pot, so long as the resistance, taper, thread, and shaft style match. Locating lugs might be more difficult to match.

[Anonymous No.2742618]

what temp should my soldering iron be?

[Anonymous No.2742619]

>>2742618
Whatever temp you want it to be. Are you a pimp or a ho?

[Anonymous No.2742631]

>>2742618
300-380C
Anything below 300C is too cold for pretty much any type of solder.
Anything above 380C is guaranteed lifted pad.

[Anonymous No.2742654]

>coincidentally move a magnet near my copper wool tip cleaner
>it sticks to the magnet
wtf
did these fucks sell me copper coated steel wool to fuck up my tips with?

[Anonymous No.2742658]

>>2742654
Seems to be so. Also, I thought it was supposed to be brass wool.

[Anonymous No.2742659]

>>2742654
>did these fucks sell me copper coated steel wool
Yes
>to fuck up my tips with?
No. Its fine.
Next time buy brass wool. Usually, it is still real brass.

[Anonymous No.2742685]

Hello, do you know where i can find a pcb for build a mouse to maybe sell it?
And do you know if a mouse pcb is copyrighted? Can I just open my mouse, take the pcb and copy it ? If its patented how can i know the patent used and if its expired?
Thanks

[Anonymous No.2742692]

>>2738353
What's the best way to drive a stepper motor controller from a Windows PC over a USB connection with Python programming?

[Anonymous No.2742785]

>>2742093
That's awesome! Post ROV.

[Anonymous No.2742788]

>>2742631
I have to turn mine up for COB LED pads or thick wires. The ideal iron would have a bigger/configurable overshoot. Such an iron might not need temperature adjustment to compensate for variable pad thermal conductivity.

[Anonymous No.2742809]

>>2742788
Or just buy a thermally balanced iron and be done with things. They're the cheapest and most readily available type of iron so no excuses.

[Anonymous No.2742835]

>>2742654
Maybe it's copper-plated nickel. I mean it won't be, but you never know. I suspect steel wool is too abrasive for soldering tips, but I guess it depends on the alloy.

>>2742685
There's a few gaming nerds making custom mouse designs for various reasons. Look for an open-source hardware design you can rip off. /g/ might know, they do that kind of stuff with keyboard designs on the /mkg/. Also see datasheets/appnotes for mouse sensor ICs.

>>2742692
Stepper motor - stepper driver - MCU with native USB / MCU with USB-UART bridge - computer
Common arduino nano boards have more than enough processing power and come with that USB-UART bridge IC built-in, so it would be pretty easy to just plug that into the computer. On the PC side, it's very easy to interface with a serial port using python.

>>2742788
If you were able to put the temperature sensor and element in extremely close proximity to the tip such that there was negligible thermal resistance, you wouldn't need to worry about PID tuning to prevent overshoot, and so wouldn't need to turn up the temperature for heavy-duty work. I think I'll get a JBC T245 handpiece and tips and make myself a 200W station, though Metcal's induction-heated tips look pretty cool too.
>The ideal iron would have a bigger/configurable overshoot
I know the TS100 and Pinecil and T12 series of irons can have custom firmware. The official JBCs remember calibration data for different tips, and even learn about the kind of thermal load you're soldering as you do so.

>>2742809
Unregulated irons of a convenient size won't even touch a COB, or any aluminium-backed PCB. Because their tip temperature is directly a result of the thermal resistance from the tip to the workpiece, anything that sinks heat significantly will drop the temperature below what you can solder at. An unregulated iron with enough power to reflow a joint on a COB would be so large as to be too chunky to desolder a D2PAK. You'd be more sensible suggesting a butane iron.

[Anonymous No.2742840]

>>2742835
>An unregulated iron with enough power to reflow a joint on a COB would be so large as to be too chunky to desolder a D2PAK
I don't know what you're smoking. Fancy temperature feedback irons can easily be 150W or higher in a fairly small size, why would you think a thermally balanced iron can't be just as powerful in the same size?
>inb4 the local shartmart doesn't sell them so they don't exist

[Anonymous No.2742847]

>>2742835
>Unregulated irons of a convenient size won't even touch a COB
>"Cheap irons can't have big resistors because they just can't, okay? Big resistor only for expensive iron"
At least tell us who's paying you first.

[Anonymous No.2742885]

>>2742444
To me it seems like you don't need a separate regulator, the VBAT pin accepts up to 5.5V, generates 3.3V on DVDD which the can supply the other power pins. If you use an external microcontroller, connect it's supply voltage (up to 3.3V) to PVDD to make use of the internal level shifter.

I was about to give advice about grounding and such, but 13.56MHz is slow and barely counts as RF. Wavelength is about 23m, a 10th of that is your maximum trace length without treating it as a transmission line. So no worries here.

You have quite a few unconnected pins. Unless you are absolutely sure you don't need them, I'd recommend at minimum a small pad (0.5x0.5mm) so you can easily solder a wire for debugging.

[Anonymous No.2742897]

>>2742835
The temperature sensor could be a MLX90640 to directly see the temperature. Is the jbc controller described somewhere? It seems like a self tuning controller could learn the time constant. I'm not optimistic about the identifiability of the solder heat of fusion.

[Anonymous No.2742911]

>>2742506
I cleaned the volume pot and it fixed the issues there. Thanks for that bud.

My new issue is a bit more odd.
On AM mode and FM modern the left speaker is very quiet. On phono(record player) both work fine. On tape mode the left is quite and the right is completely off.

Any video on that one? All of the caps look great I can see.

[Anonymous No.2742916]

>>2742840
>>2742847
>why would you think a thermally balanced iron can't be just as powerful in the same size
For the temperature at the tip to not get into stupid hot levels when it isn't touching a workpiece, heat must be lost to the surroundings. The higher the constant power draw, the larger the surface area needs to be to dissipate this heat. See 80W and 120W Weller irons as an example. 60W is a bit more sensible-sized, but that's 60W all being dissipated as heat when the tip is at its maximum temperature of ~450C or so. If you want to get maybe 40W of heat into the workpiece, you've still got the same amount of surface area but that surface area is only dissipating 20W now, so the temperature for it to be at equilibrium must be significantly lower. The effective power output of an unregulated iron is hence significantly lower than a regulated iron can be. A temperature controlled iron would get up significantly above 500C if you left the element turned on because it lacks this high surface area, as happened to me a couple of days ago when the MOSFET died short.

Note that this limitation doesn't apply to PTC-element irons to nearly the same extent, and not at all to curie-temp irons. If you see a 70W+ iron that doesn't have a shank that's <15mm wide and <120mm long, it's probably PTC-element. Some irons have a button to enable a higher power mode (e.g. 20W default 120W max), which is one way of doing it, but considering you can buy an iron with digital temp control that uses 936 tips for like $30, I don't see a reason to bother with any unregulated iron.

>>2742897
>Is the jbc controller described somewhere
I know Marco Reps went into the details somewhat, but reading their own documentation is probably for the best if you want to understand their full feature set. On the other hand, people have definitely made their own JBC controllers, maybe they copied these features.

>>2742911
Open up and clean the mode selector switch the same way you did the volume pot.

[Anonymous No.2742928]

>>2742916
>you can buy an iron with digital temp control that uses 936 tips for like $30
And then you break the bank on tips if they happen to be shit and crater on you. No. Any iron that uses proprietary tips has the potential to be a money drain. Maybe you're okay with playing russian roulette with your wallet, but that doesn't mean everyone else here is.

[Anonymous No.2742949]

>>2742916
>If you want to get maybe 40W of heat into the workpiece, you've still got the same amount of surface area but that surface area is only dissipating 20W now so the temperature for it to be at equilibrium must be significantly lower
Bigger resistor = more power. It's simple and easy to understand. Instead of having an iron with a 40W heating element you should be able to get one with 60W or 80W instead. But according to you it's not possible. I guess Big nichrome won't let you talk about why only fancy shit can have more powerful heating elements.

[Anonymous No.2742962]

>>2742928
Official 936 tips from Hakko are like $7-9. From the chinks they're maybe a dollar each, probably less. I'm not talking cartridge tips over here, if you can't afford to spend $8 on tips every year or two, perhaps this hobby isn't for you. For comparison, T12 cartridge tips from Hakko are $20-30 each, which if they last you a couple of years minimum could well be worth it. Heck, my $10 chinky T12 tips have lasted me over 3 years now, even after one got above 500C.

There's nothing intrinsic about the tips of regulated irons that mean they have to be more expensive than the tips of unregulated irons. In fact, because an unregulated iron will get up above 450C when it's not being put to the workpiece, its tips will probably last somewhat less long than a regulated iron. Same applies to the element itself.

>>2742949
>you should be able to get one with 60W or 80W instead
I never said you couldn't, just they're physically bulkier and unsuited for the kind of SMD soldering you'd want for an aluminium PCB.

My points are:
>an unregulated iron has to be larger for the same power consumption compared to a regulated iron, because it has to dissipate all its heat into the air
>an unregulated iron is less efficient at transferring its power to the workpiece, because some of this power gets dissipated into the air
These compounding features mean high-power irons for precision work are a shitty compromise.

[Anonymous No.2742972]

You can make your own PCB preheater with a halogen bulb. Use two or more thermocouples and a PID control loop + fan. Bonus if you have a thermal camera.

[Anonymous No.2743076]

>>2742916
It looks like Marco Reps did bang bang control using the JBC tip's built-in thermocouple. Later on in the video he excuses the overshoot, and says other irons also do it, but putting it on the screen would create problems for the customer service department. www.jbctools.com/soldering-assistant.html displays no overshoot.

[Anonymous No.2743104]

>>2743076
I meant in his video where he tests actual JBC equipment that he gets through welectron.

[Anonymous No.2743126]

>>2742618
600-750F, I tend to use around 600-650. better to try at 600 and work your way up

[Anonymous No.2743131]

>>2742962
>if you can't afford to spend $8 on tips every year or two, perhaps this hobby isn't for you
They could last a year or they could last all of 30 minutes. I can't know until I buy the damn thing. And if they don't last a good while then I wasted a bunch of money on an iron that cannot be used practically. I already have a pinecil gathering dust because of this exact issue, I don't want any more.
>inb4 the damage control team drops by and says I did/didn't do X,Y,Z

[Anonymous No.2743152]

>>2743131
>They could last a year or they could last all of 30 minutes
They're made by Hakko, these exact tips are used professionally. You're not going to get the chink tip experience unless you're doing something wrong. Get the Weller or Goot or whatever equivalent of the 936 tips if you have different brand leanings, while you might not be able to buy a mains-powered regulated iron that uses them, there's a lot of projects that use official handpieces as well as tips, with a custom MCU-based controller.
>damage control team
If you can get some tips to last over a year, you should be able to get any non-cheese-grade tips to do the same. If you got that kind of experience, chances are it was a QC issue, either with the iron getting too hot, or the tip being cheese-grade. There's a tiny possibility that you're using a solder alloy that the tips are incompatible with, I've heard lead-free is worse for dissolving stuff but I've never had that problem. I don't trust Pine64 to ship their irons with Hakko-brand tips at that price.
>inb4 you're a boomer who files your tips or uses acid flux

[Anonymous No.2743171]

>>2742962
>>an unregulated iron has to be larger for the same power consumption compared to a regulated iron, because it has to dissipate all its heat into the air
No, it doesn't. The point of a soldering iron isn't to dissipate heat into the air. It's to put heat into a solder joint. Compact high power heating elements exist so there's no excuse for it.
>an unregulated iron is less efficient at transferring its power to the workpiece, because some of this power gets dissipated into the air
All irons lose heat to the surrounding air. Your 500$ IoT connected bluetooth garbage is subject to this just as a 5$ chinkshit plug in iron is.

[Anonymous No.2743183]

when i was looking at the SSM3J328R P-MOSFET datasheet, i saw that it had a diode forward voltage.
what exactly does this mean? does the MOSFET just act like a diode and drop the voltage between its drain and source?

[Anonymous No.2743192]

>>2743183
That's probably the drop of the body diode.
In case you didn't know MOSFETs have a diode between source and drain. In normal operation that's reverse biased because the voltage at the drain will be higher than at the source so it never conducts. If you fuck up and forward bias it somehow then it will function like a regular diode, voltage drop and everything.

[Anonymous No.2743206]

>>2743152
>They're made by Hakko, these exact tips are used professionally
That's what /ohm/ said a couple years back about the pinecil.
>You're not going to get the chink tip experience unless you're doing something wrong
Ironic, considering the good tips I'm using now are from chink irons.
>If you can get some tips to last over a year, you should be able to get any non-cheese-grade tips to do the same
Considering how much money I already lost on "good" tips that cratered in under an hour, I'm still reluctant to try it out again.
>or the tip being cheese-grade
This is the problem and I'm tired of pretending it's not. Even big brands sell garbage tips nowadays.
>you're a boomer who files your tips
Only the cratered ones so I can use them for a little longer. If there's one upside to the shit tips that I've tried it's the thermal characteristics. They're much better at heating things up. Of course, the downside is that they slowly disappear on you as you use them, but it all works out because the vast majority of solder jobs don't need that much heat so use time is limited.
>or uses acid flux
I rarely have to use any extra flux at all, whatever's in the solder is enough for me. Should be rosin according to the label.

[Anonymous No.2743220]

>>2743206
Is it RA flux? With lead-free solder?

[Anonymous No.2743278]

You know if a can copy a pcb for exeample microwave oven pcb to mass production and sell it, or its copyrighted? Thanks

[Anonymous No.2743281]

>>2743278
It's bound with IP laws, but if you reverse engineer it, it's fine.

[Anonymous No.2743282]

>>2743278
You can get around copyright by hot gluing a cloned computer mouse to the microwave and then filing a patent.

[Anonymous No.2743297]

When I reverse engineering a pcb, what should i modify to be not like the original? A capacitor?
I just want to know, indeed they are +20yo microwave if i really want to copy easly, and we developed there thanks to the copy, if people taked improvment for themself they are not improvment

[Anonymous No.2743300]

god motherfucking damn anons. how many battery types are out there? i needed to replace my garage opener battery and i tossed the old one and put a new chody one but it turned out to be too thick. turns out there is another chode that looks very similar: the girth is somewhat between AAA and AA but they are short. One of them is 12V and the other one is 1.5V. I am guessing I need 12V in the old garage opener? it is too old I can't find anything on google.

[Anonymous No.2743301]

[Anonymous No.2743303]

>>2743297
I doubt you plan to use only that one PCB you're trying to copy so an easy way to modify it would be to integrate elements from the other PCBs you will be using. Or just merge them side by side, that also works.

[Anonymous No.2743304]

>>2743300
breh searching 12v remote battery immediately gave me the usual suspect. Step up your search game.

[Anonymous No.2743308]

>>2743304
Yes I found it but I am saying I don't know if I need 12v or any other similar type. There is no indication on the remote what type of battery it takes. I said I am _guessing_ it is 12V but there are garage openers that take a 1.5V cell.

[Anonymous No.2743335]

>>2743308
What's the model of garage opener? Look up the user manual.

[Anonymous No.2743341]

>>2743126
Yeah, that’s why I just put mine on a light dimmer. I get fine temp control, because every joint has different variables.
Those microprocessor controlled soldering irons are hilarious equivalents to listening to AM radio on an audiophool-grade hi-fi system.
You’ll look back on it and laugh.
I’ve used and had several high-end weller industrial soldering stations, and I can’t even tell the difference.
My favourite thing though is the temperature controlled hot air stations, where the temperature changes at 10 ℃/mm distance from the part.
Why do I even put mine on a dimmer you ask? I usually turn it down to where the tip isn’t oxidizing so fast and turning the solder tinning on it a dull, matte grey colour—that’s too hot.
I’m using my soldering guns more and more, after I started to watch that based diode gone wild guy. Need to solder a lug on to a metal case, or replace a 100 A +5 V rail wire on a PSU? Soldering gun.

[Anonymous No.2743347]

>>2743308
>I don't know if I need 12v or any other

99% sure you need a 12V A23, also known as 23A.
reason being that, in order to get a large enough radio signal, you need way more DC voltage than a 1.5V cell can give you.

[Anonymous No.2743352]

>>2743347
Mine use CR2032 coin cells.

[Anonymous No.2743355]

>>2743171
>The point of a soldering iron isn't to dissipate heat into the air. It's to put heat into a solder joint.
Yes, but when you're not putting any heat into the solder joint, the iron is still consuming the full 60W or whatever from the wall. It doesn't draw more power when you touch it to a joint and less power when you take it off the workpiece.
THAT HEAT HAS TO GO SOMEWHERE!
An unregulated iron has to have the large surface area to dissipate its full power rating into the air without getting unreasonably hot. If you don't have that high surface area for dissipating heat into the air, the iron gets so hot it glows when you're not touching it to the workpiece. Looking at some datasheets, it looks like regardless of power rating, unregulated irons tend to idle at ~480°C.
My second point follows from this first one.

>>2743206
>That's what /ohm/ said a couple years back about the pinecil.
As I said, I really doubt the Pinecil shipped with Hakko tips, considering they're almost as expensive as the iron.
>Ironic, considering the good tips I'm using now are from chink irons.
I think it's fairly safe to expect that western/jap name-brand tips will outlast similar tips that will be more likely to not dissolve, but that doesn't mean chink tips will always dissolve. My chinky T12 tips have lasted me well.
>Even big brands sell garbage tips nowadays
Do they? I've never heard people complain about legitimate tips before.

>>2743297
Definitely change the board layout, chances are the schematic is following a reference design, but I'd want to take cues from different brands of microwave oven just to be sure your thought process is sufficiently diverse. Changing some component values isn't a terrible idea either, and I'd naturally swap out any MCU for one that you're more familiar with. One that's easy to flash custom firmware on.
Though if you do plan on selling such a thing, it would be worth shelling out to see a copyright lawyer.

[Anonymous No.2743360]

>>2743347
Yes that's what I thought and it is most likely the case. The rolling code chip from microchip VCC=3.5V to 12V.

>>2743352
Exactly, same with my other remote that works with the same door. That's what confused me.

[Anonymous No.2743402]

>>2743341
My soldering colleagues actually think Weller is shit, they're all into JBC.

[Anonymous No.2743468]

>>2743402
> JBC
> cool trendy black color
Never heard of them. See picrel.

> Weller
They made all kinds of stuff, they’re probably only aware of the home retail lines. See picrel.

[Anonymous No.2743590]

Anyone know much about lighting electrics?
After waiting over 2 months for the landlord to get the kitchen lighting fixed in this new unit I've decided to take matters into my own hands.
>light itself is all secured and connected in the recess
>open the switch panel
>pic related
I'm no electrician but that doesn't look right to me.

[Anonymous No.2743592]

>>2743590
Copied the layout from another switch and got this, but then the light is permanently on. Still a great improvement.

[Anonymous No.2743614]

>>2743590
I’m assuming ‘hot’ is red, and black is neutral?
Then what is white?
In Britain we now use brown for ‘hot’ now, and blue for neutral, labelled ‘B’ and ‘B’ respectively so they can be easily distinguished.

[Anonymous No.2743624]

>>2743592
Is the light meant to be controlled by multiple switches? The red+white wires look like the two wires that go between a pair of SPDT switches. But if that's the case, you shouldn't have three lives going into the common terminal of the switch, it should only be 2 (assuming two are from the light circuit). Pic related is how I think multi-switch lights are wired up. Usually power goes into one switch, and out the other switch to the light. You might need to flip the breaker, disconnect all the wires, and use a meter to figure out what's connected to where.

[Anonymous No.2743625]

>>2743614
>>2743624
You're right, it should be two way lighting, I had no idea because the other switch didn't do anything except turn on a bathroom fan (despite being 5m down the hallway and no where near the bathroom which has its own fan switch).

[Anonymous No.2743652]

>>2743625
Wired them both up similar to that diagram except one is red on 1 and white on 2 so that it's flipped and when both are off the light is off.
Took out the extra two active lines from >>2743592
The third red in C is going to the light and I left that one there. The other switch has two active lines going into its C.

Now the only issue is one of the switches seems to be broken because while the "off" (2) position works fine, the "on" (1) position has no connection to C so it just breaks the circuit and functions as a full off. Guess it's a buggered switch.

Good enough for now, eventually the actual electricians should be around to have a look at it.

[Anonymous No.2744035]

What kind of micro controller do I need to build a macro 3×3 macro pad with a rotary knob. More accurately, what options do I have.

I own;
>a 3d printer
>brown switches
>tons of keykaps
>wires
>solder
>solder iron
>Flux
>random hardware such as little screws and bolts
>a 10 dollar coupon to microcenter

[Anonymous No.2744061]

>>2744035
Raspberry pico, you can even get wireless boards.
Or you can make your own custom board with a RP2040 chip.

[Anonymous No.2744069]

>>2744035
ESP32S3 or ESP32C6. Both bluetooth and wifi, with native USB. You could write a little web interface for configuring it over wifi, and have it act as a bluetooth keyboard peripheral as well as a USB peripheral. The S3 also has ethernet hardware, which is good because ethernet is objectively better than USB.

[Anonymous No.2744071]

>>2744069
Forgot to mention Seeed Studio XIAO RP2040. Type-c and rgb led.

[Anonymous No.2744081]

>>2744071
>Seeed Studio XIAO RP2040
It only has 11 GPIOs, but that's marginally enough for this kind of pad. While reconfiguring them via USB is reasonably convenient even for the ohmless, it requires pushing a boot button, which you'd either need to break out to the outside of the pad, or to take it apart to change the configs. Maybe there's the option of configuring it through custom usb drivers or whatever gaming mice do.

The ESP32C6 dev-boards also have type C and an RGB LED. A bit larger, but the extra pins might be nice to have for charlieplexing or whatever. Not sure if they can be programmed without pressing a boot button, but using wifi is a nice option.

[Anonymous No.2744087]

>>2744035
rp2040-based boards are a good modern choice. Load it with the KMK firmware, a python port of QMK, and you're off to the races.

[Anonymous No.2744134]

>>2744061
>>2744069
>>2744087
>rpi
>esp
why people always suggest this overrated trash. literally could use any fucking microcontroller that has a usb peripheral on it. of which there are 100s

[Anonymous No.2744138]

>>2744134
There's something to be said for using widely documented and supported chips, especially for a simple project as a beginner. There's already existing firmware and libraries for keyboards, and it has enough performance headroom to not be a burden.
If you're making some embedded system for mass production, of course you'll pick the cheapest and most abundant chip that can handle the task. For a one off hobby project, the extra couple dollars it costs is easily worth the convenience.

[Anonymous No.2744150]

>>2744134
not every micro with USB is capable of holding and running python effectively. the 2040 is also super cheap, there's no reason not to use one instead of a chinese arduino clone.

[Anonymous No.2744158]

>>2744134
They're both cost effective options that are easy to program, are readily available, can be found already on boards of a variety of form-factors, and already have a large amount of code written for them that does a similar thing to what the OP is asking. Yeah sure OP could buy an 8-bit CH552 for 60c (though the 32-bit CH32V203 is just as cheap), but it's a chinky MCU without an established codebase or toolchain. The traditional ATmega8U2? That's $2, literally twice the price of an RP2040. The ATmega32U4 is $5. Why the fuck would anyone use one of them? PICs are no cheaper. The ESP32-S3 is more like $3-4, but it already comes with the bluetooth and wifi networking ability out of the gate.

[Anonymous No.2744161]

>>2744087
>KMK firmware
Huh, pretty neat. Already have some spare pico boards and rotary encoders lying around, may have a go at making a volume knob myself.
Not sure how well it will perform being based on uPy but not like there's much to lose.

[Anonymous No.2744162]

>>2744161
keyboards aren't exactly the most performance intensive application

[Anonymous No.2744167]

>>2744162
Good, because they usually only halfheartedly support USB 1.0 or 1.1 instead of something sensible. The only thing USB 1.1 has is that it’s the last thing your home-grade oscilloscope can look at.
The “western” chips are so expensive because they’re busy paying off the thousands of patents and patent trolls (such as themselves) in a huge, self-defeating human-centipede ring.
The chinese don’t give a flying fuck, and end up supporting hobbyists with reasonable prices.
> rp2040 documented
Hahaha… no. We’re still trying to figure some things out. You’d think that RPF would know, but no—it’s obvious they had a lot of help from the fab’s design engineers and didn’t want to see the details.

[Anonymous No.2744186]

>>2744167
>We’re still trying to figure some things out
Such as? Just curious since I haven't run into any documentation issues while using it.

[Anonymous No.2744198]

>>2744138
>widely documented and supported chips
Which ESPs and RPis are not. The arduino boards take this spot, no matter how much you hate it.

>>2744158
2$ gets you a full arduino nano, not just a chip. If you know where to look, that is.

[Anonymous No.2744215]

>>2744167
>support USB 1.0 or 1.1 instead of something sensible
Getting the clock rate to do high speed (480Mb/s) isn't trivial for a cost-optimised MCU. If you ever do need that kind of speed, chances are you're doing it for raw data streaming and so can use a chip like the FT232. If you're in an odd case where an FT232 won't work, then I'd probably be using an FPGA to bit-bang it.

>>2744198
>arduino nano
Does not have native USB capability. The USB port is connected to a CH340G, which can only emulate a USB serial port, it cannot do USB-HID unless you write code to convert it to do that on the computer side. Technically you could program it to use V-USB, but that's an awful and unreliable hack. There's a reason all USB keyboard projects ask you to use a Leonardo or Pro Micro.
>If you know where to look, that is
The 328P chips themselves are $2 in individual quantities, $1.50 in bulk, from a proper supplier like LCSC who gets them from Microchip. It's not out of the question for chinks to buy these and slap them on a 10c PCB with 15c of other parts for 15c profit. Though I suspect their chips may be QC rejects. Or ATmega168Ps, I've got one or two nanos with them. The ATmega32U4 has roughly the same specs as an ATmega328P, but has native USB support, for more than twice the price. Again, why would someone not just get an RP2040.
>documentation
>support
The RP2040 has more than enough of those for 99% of users. Only the people who are doing real obscure or critical stuff with the M0 core will prefer to use something more established, namely an STM32 of some variety.

[Anonymous No.2744226]

>>2744215
> usb 2 is too hard
If motorola can do 100 BASE-T ethernet on a 8/16 bit 68hc12 @ 25 MHz over 20 years ago, I feel that USB 2 should be doable on an rp2040.
Maybe the RPF weren’t sure USB would catch on, but there’s over a dozen products that use USB nowadays.

[Anonymous No.2744232]

>>2741946
>>2741956
So it is interesting. First of all, it was just 1500W, not 2200W. Second is that adjustment of power is interesting. "800W" to "2200W" is smooth, below 800W it cycles on and off, which is pain in the ass if cookware isn't high thermal mass, like idk, cast iron skillet.
It has temperature control which works... OK. Could have been less overshoot, but id say it works.
I think I know the reason why power adjustment is so shit when you get below 800W. Shit is meant for 50/60Hz mains, and this means you'd need some sort of zero crossing detection to just waste cycles of main, and possibly detect if its running on 50 or 60 Hz, which is possible to do with microcontroller, but idk what micro did they use and if it has more hardware comparators or whatever.

Also shit didn't want to work with my stainless cookware. Idk why, I tested and bottom was magnetic, but I guess not every magnetic stainless has resistance high enough.

I wonder now, in future, would we get GaN or SiC based cookers, that can run at higher frequencies to work with non-magnetic stainless and aluminium?

[Anonymous No.2744270]

>>2744150
why in the fuck would you ever want to put python on a microcontroller. fuck me dead thats the most retarded thing ive ever read on this site

[Anonymous No.2744279]

>>2744270
RP2040's main feature is micropython.

[Anonymous No.2744308]

>>2744279
Which makes it omega gay and retarded. It was already retarded enough for coming in a package that is basically unusable by hobbyists as is. At least the atmega 168/328 have exposed leads that can be soldered by someone skilled enough.

[Anonymous No.2744315]

>ur recommandation is bad!!!
>doesn't recommend anything to counter it
Lmao, all talk no dev.

[Anonymous No.2744324]

>>2742835
I'll go the Arduino Nano route then, thanks.

[Anonymous No.2744382]

>>2744279
What the fuck am I reading. It's just an ARM chip.

[Anonymous No.2744390]

>>2744279
I'm no expert on this but I'm pretty sure it runs machine code internally and you could program it with any language that has a compiler that spits out said machine code.
Basically micropython isn't that big a deal besides kicking the nuts of all arduinofags that can't into python.

[Anonymous No.2744412]

The longer you look at this, the more painful it gets.

It's apparently from a Russian drone.

But I also want to ask you, what in the world could the bottom component on top of the brass block be?

What development board is that?

[Anonymous No.2744426]

>>2744412
Small square puck with a single wire sticking out?
Seen gps modules like those. But surely russian army would use GLONASS and those are on bigger modules.

[Anonymous No.2744428]

>>2744412
Green PCB kinda looks like what USSR industry did in the past... Except solder mask, they never did it for some reason.
It also has typical russian silkscreen on it, a poorly made one (for some reason they only make nice silk screen for component names, like if western PCB layout doesn't talk cyrillic or something, and then add russian letters and other stuff by hand). So it is probably locally made PCB.
>aliexpress xlsemi DC-DC
lol
Seriously? This shit has like 100 mV of noise on the output, that you can't fix with capacitors too.

[Anonymous No.2744431]

>>2744426
nah cant be GPS nor GLONASS. It has four unshielded wires going in. The package top looks like it can be removed so its some how calibrated at factory via that opening. Seems to produce alot of heat because of he brass heatsink.

Also no shielded antenna coming out so no communication related.

>>2744428
I have seen that dev board but cant put my finger on it.

[Anonymous No.2744433]

>>2744431
bottom sensor/relay/important mosfet seems to be vibration sensitive (but its still on huge brass plate :D

[Anonymous No.2744448]

>>2744412
Looks like a cool bomb prop. Defuse by cutting the correct VGA cable, if you get the wrong one it and the hero explodes.

[Anonymous No.2744451]

>>2744270
Because compiling and flashing is the worst part of using them, whereas with python I can just plug it in as a USB device and drop the new file on. If you haven't tried it you haven't lived.

[Anonymous No.2744453]

>>2744308
QFN is easily hand-solderable casual, i bet you use 1206

[Anonymous No.2744464]

>>2744444
juss checkin

[Anonymous No.2744466]

>>2744448
>VGA
<DB-9

Please stop using the internet

[Anonymous No.2744468]

>>2744464
yes, it's the overhang, or your temps are too hot, or you have insufficient part cooling. wrong general btw.

[Anonymous No.2744469]

>>2744466
Party pooper.

[Anonymous No.2744470]

>>2744468
You got it all wrong, Anon. That wasn't my post, I was juss checkin the quints.

[Anonymous No.2744495]

>>2744232
There would need to be an induction cooktop cartel to want to go to aluminum. Besides, you shouldn’t want to cook with aluminum, unless it’s inside SS.
My all-clad works fine on induction.

[Anonymous No.2744497]

>>2744226
>I feel that USB 2 should be doable on an rp2040
It can be overclocked a fair bit faster than the default, I wonder if one could hack the USB hardware into acting like a high-speed device.
Again though, what purpose would you have for USB 2?

>>2744324
Get a TMC2209 stepper driver too while you're at it.

[Anonymous No.2744504]

>>2744308
Yes.
And please, for the love of god, stop making carriers and things with “castellations” — it’s not cool, it’s just retarded, trendy, cheap nonsense.

We had the GOAT, and let it slip away…
Surface mountable, socketable without bent pins, DIPable with the same pins straight. It’s all things to all people.

[Anonymous No.2744511]

>>2744412
That dev board looks like it has turrets on it to connect the wires. I love turrets, but they’re expensive nowadays. We used to see them more in Tube-era designs.
That board probably is a DSP board simulating a circuit of five tubes since they’re no longer available and it just slots into the original design.
The tube transformers (i.e. with the 6.3 V filament line) were replaced with chinese buck/boost converters.

[Anonymous No.2744528]

>>2744526
>>2744526
>>2744526
NEW THREAD

[Anonymous No.2744584]

>>2744279
Uh, no?

[Anonymous No.2744598]

>>2744495
>Besides, you shouldn’t want to cook with aluminum, unless it’s inside SS.
Meh, bare aluminium is better than teflon coated aluminium, because I don't like teflon in my food.
>There would need to be an induction cooktop cartel to want to go to aluminum
Idk, thing is that induction cooktops existed for years, apparently they existed back in 1970s.
Problem was that back then high-power transistors didn't exist (eh... they were expensive), and they were rather low frequency.
Then came '00s and MOSFETs and IGBTs became a thing, but they all are slow, 50kHz is max you can get from a typical IGBT.
But with GaN and SiC you can have much higher frequencies IIRC, for much lower cost.

[Anonymous No.2744652]

>>2744451
>>2744390
sounds like virgin software developer cope if you ask me

[Anonymous No.2744788]

>>2744451
There's virtually no difference with using gdb with something like libocd.
Also you can just install a stub 'server' on the device and push bits to it. All you need are the three commands 'clear', 'push bits' and 'jump to' and you can use any language to implement any workflow. No need for py "slow and broken" thon.