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Thread that perished: >>2981579

>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.
Read the datasheet.

>OP source:
https://github.com/74HC14/ohmOP
bake at page 10, post in old thread

>Comprehensive list of electronics resources:
https://github.com/kitspace/awesome-electronics

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

>Books:
https://libgen.is/

>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
Horowitz and Hill, The Art of Electronics

>Recommended software tools:
KiCAD 6+
Circuitmaker
Logisim Evolution

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

>Most relevant YouTube channels:
W2AEW
Moritz Klein

>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
>>
>>2989599
>suspiciously placed huge walnut with an eye in the middle
>>
I saw a guy 3D print normal plastic with the traces of a PCB layout embossed into it. He then stuck down copper foil/tape and sanded off the high-spots, leaving just the embossed traces. Soldering it would definitely soften the plastic, but if you do it quickly it shouldn’t be an issue even with PLA.

But the best way is definitely a fibre laser. They can punch holes through the FR-4 that are charred, allowing you to electroplate them with copper. I think dual-colour lasers can also make un-charred holes and slots and edge cuts using an ultraviolet or blue laser, but I’m not sure. Blue is definitely better for cutting through copper than IR.
>>
>>2989609
>huge walnut
looks regular-sized to me.
wtf are pogo pins for?
also, anyone noticed a fuckup?
>>
>>2989623
Pogo pins connect to the antenna, the thin metallic thing stuck to the inside of the shell. Obviously not a big deal considering it worked without the lid on.

Maybe some smoke started quickly offgassing when the last of the batts were soldered on? Hard to say.
>>
>>2989624
Shorted the batteries with his tweezers turned the tip red hot.
>>
>>2989610
>even with PLA
Doubt, but maybe with a lot of flux and high temperature one can do it.
>>
>>2989674
It takes like 5 seconds max to make a joint to a non-power component. Even if the plastic under the component melts, if you don't deform it it won't be an issue, and it won't heat up enough to impact the structure of the whole board. Unless you're making 10x10mm mini boards. Making your board like 3mm+ thick probably helps.

You can always anneal your PLA.
>>
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>>2989599
>Where to get started?
Babby's first circuit.
>>
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>>2989690
>Babby's first circuit.
>>
>>2989676
Pla is half-step up from hot melt glue… it melts in your car.
The whole premise is ridiculous.
Real PCB material is probably cheaper than the pla.
>>
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>>2989624
>antenna
ahhhh, right! ty.
>>2989628
>Shorted the batteries with his tweezers turned the tip red hot.
yep. space is so cramped that when he released the pressure on the tweezers, he ended up shorting positive to the ground.

wtf do you even find lipo cells this small? in vapes or some shti like that? I think I've seen a vape battery in a video someone did and they looked bigger tho...
>>
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>>2989706
If you anneal it, the heat deflection temperature goes up past ABS or even polycarbonate, to 150C or so. To anneal something flat, just turn your bed up to 100C after it’s printed and chuck a towel over it for an hour. If you’ve ever tried to plastically weld with a soldering iron, you’ll have a good idea of how poor a thermal conductor plastics are, only a few millimetres around your iron tip gets molten. If thats beneath a layer of copper, then it will hold its shape.

Fibreglass FR4 can’t be 3D printed, so its cost is moot when discussing this method of prototyping. You could print a negative then apply a thermoset resin like epoxy, maybe with fibreglass, and do the same technique on that instead. But epoxy is definitely more expensive per kilogram than PLA.
>>
>>2989720
>watching some man from africa read a chatgpt script
ishygddt
>>
>>2989728
sounds like you watched it, senpai
>>
>>2989720
nigger
>>
>>2989725
> PLA
Is literal waste from making greek yogurt, they didn’t know what to do with all the lactic acid from the processes until 3D printing came along.
>>
>>2989745
Pretty sure it’s corn/maize derived. Biodegradable if you own a 50C+ bioreactor!
>>
>>2989745
>Is literal waste from making greek yogurt
Hey! They could mix it with some fluoride (waste from steel making) and put it in our toothpaste.
>>
>>2989747
> Biodegradable if you own a 50C+ bioreactor!
No, 50 deg C won’t do it any longer… I’ve been tempering it my PLA. Over and over. So now it’s harder than a diamond, denser than osmium, and melts 5 times higher than tungsten.

Actually, I’m thinking I can make PCBs from Turds if I temper them….

I can’t afford a $2 phenolic FR2 PCB after I bought a $3000 printer and a $1500 PLA drier, and a PLA subscription service. I’m glad I can eat the PLA though… thanks for letting me know.
>>
Do I recall correctly that surface mount electrolytic capacitors are difficult to hand-solder? I made my layout with thru-hole ones instead. I need a 1 uF bipolar capacitor to remove the DC offset from an audio signal and I've heard that ceramics have "microphonics".
Also does anyone know a good SMT equivalent of the 1N4148 diode? I found one with a SOD-523 package but I think that might be a bit on the small side, all my other components are 0805.
>>
>>2989730
10 seconds of it, Big Chaks.
>>
>>2989757
>capacitors
What's the cap doing? Doesn't look like it's a cap to ground, for any series caps in an audio circuit I'd want to use film caps. Though if it's under constant DC bias, an electrolytic isn't the end of the world, they can actually be pretty low leakage if you overspec their voltage rating. Polymer electrolyte caps should be better than conventional liquid electrolyte caps by any relevant metric.

>a good SMT equivalent of the 1N4148 diode?
1N4148W is what I'd go with. The WS is a small and somewhat delicate SOD-323 package (still larger than a SOD-523), but the W is in a larger SOD-123. There's also always MELFs, which are bigger still. Pic related shows MELF, 123, 323, 523.
>>
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>>2989780
>>
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Question for /ohm/: is there any money in electronics repair? Do people even look to repair stuff in 2026? Can you even make a living wage with it?
>>
>>2989790
Yes, but it seems tough. I know a guy that specialises in television and home audio, he does both home-call installation and repair. So I guess he's already effectively filtering for whate repairs are and aren't worth attempting. Because of the labour cost, you can only really effectively repair things that are sufficiently valuable. If that's new electronics, then it's often difficult to repair thanks to tiny SMDs, custom programmed MCUs and ASICs, and proprietary software tools. You might have a chance with those for items popular enough to heve been reverse-engineered, like smartphones, but microsoldering doesn't seem very appealing.

The market I'd aim for is analogue audio, especially vintage stuff but not only. Recapping amps and crossovers is easy on the eyes and the hands, while you're at it you can sell them bluetooth receivers and pre-terminated speaker cables. The harder fixes are still relatively easy to troubleshoot, by measuring Vbe and bias currents and such, and with repeating audio signals it's pretty easy to use even the shittiest scope. Even newer stuff can be pretty easy to work on, unless it's class-D or some sort of fancy multimedia HDMI amp.

I volunteer locally with a "repair cafe" once a month, there's definitely a lot of people out there looking to get broken things fixed. But not many people willing to pay a lot for that. If you can replace a micro-USB socket in a bluetooth speaker in ten minutes, maybe it's worth it. But more often than not it takes half an hour just to take it apart.
>>
Is easyeda stealing all my data?
>>
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>>2989780
>>2989781
Thanks, the MELF package looks like what I want, in fact I had some in a smt "practice kit" but didn't know what they were called.
The circuit has 3 caps in series at various places to remove DC bias that is introduced from OTAs, or to centre my waveform around 0 V after applying a DC offset. I think it's important to remove the DC around the filter feedback loop.
To be honest, this is not high-fidelity audio, just square and sawtooth waves, and I wonder if film caps would be overkill. I'm just using basic bipolar aluminium electrolytics on my breadboard which are about 1/8th the cost of the equivalent film cap. Easiest of all would be a smt ceramic cap but I've heard that it's "conventional wisdom" not to use them to decouple audio.
>>
>>2989797
>The market I'd aim for is analogue audio, especially vintage stuff but not only
Interesting. Thanks! I guess that makes sense.
I was hoping for some computer stuff since I know a lot more about it.
>But not many people willing to pay a lot for that. If you can replace a micro-USB socket in a bluetooth speaker in ten minutes, maybe it's worth it. But more often than not it takes half an hour just to take it apart.
Yeah, 90% of things are unprofitable since the replacement is cheaper than the time it takes to open and diagnose something.
Items that have nostalgia and sentimental value are the only things people are willing to pay to have them repaired.
>>
>>2989812
Yeah I’d just use electrolytic caps, probably 50V rated or more. Though in your case it looks like biases will be going positive and negative, so you’ll want to consider bipolar electrolytic caps.
>>
>>2989856
Out of interest I tried swapping my 1 uF bipolar aluminium electrolytics with 220 nF polypropylene film capacitors. Now my square wave slopes downwards, but it still sounds the same. I'll probably stick with the electrolytics.
>>
>>2989867
this is with the 1 uF
resonance is looking nice :^)
>>
>>2989720
Youtube is so cancerous right now, how they manage to get people to listen is beyond me.
>>
I aligned everything to the grid this time (sort of) and used a consistent trace width. I feel like the layout could be more compact, but it still comfortably fits within the 10x10cm square that seems to be some price break point at JLCPCB
>>
>>2989890
Gonna cram in some pin headers for input/output connectivity? Both for power and signals.

Also looks like a few of those blue traces could be a bit shorter, and some of the pads and vias could be spaced a bit more from nearby traces for clearance reasons. I also like to ensure vias of different nets (and any traces or footprints on the reverse layer really) are spaced apart from one another, such that the ground fill can get between them. You could also thicken up the power traces if you want, but nots not a big deal for this kind of circuit.

You can also use Mitxela’s PCB trace melting KiCAD plug-in if you want to make your boards look cooler.
>>
>>2989894
Yes this is about 95% done, I'll connect the pin header tomorrow. I know I should try and fit as much as possible on the top plane, so is it fair to say that the *number* of vias isn't so important, but I should optimize to minimize the length of traces on the lower layer?
Once I am satisfied with the connectivity, I'll turn grid snapping off to space out the traces a bit more nicely. Good pointer about the ground fill.

I'm a bit annoyed I have to waste an entire half of a dual flip-flop IC to make my frequency divider, but the single flip flop I ordered turned out to have much faster edge transition requirements than the rest of my circuit can provide. Maybe I could wire it up as a second frequency divider, to provide a sub-sub-octave....
>>
>>2989900
>Maybe I could wire it up as a second frequency divider, to provide a sub-sub-octave....
I'd just wire it up with pads to solder wires onto, and a pull-down resistor or jumper on each input if needed. That way you can wire it up to whatever you want if you ever need to.
>>
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>>2989599
i want to build a dtmf tone generator to revive a rotary dial phone without janky ass microcontrollers doing shenanigans and use a tp5088n tone generator chip, i got everything figured out except interfacing the chip with the actual phone line, the datasheet gives this very simplistic schematic, would this actually work? wouldnt the dc current of the phone line fry the transformer? for the ringing ac im not concerned since i want to place this thing after the on/off hook switch
>>
>>2989936
Maybe the transformer has a high enough ESR to handle continuous DC?
>>
>>2989599
why haven't IC manufacturers capitalized on photovoltaic inverter ICs the way they have with SMPS ICs? you can find hundreds of different ICs for buck converters, boost converters, flyback converters, full bridge converters, etc. but it seems solar is always done with an MCU.
>>
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>>2989936
>wouldnt the dc current of the phone line fry the transformer?

of course not
you'd use a 600:600 ohm transformer which is the load that a typical phone puts on the line
however, you def need a hook switch or else the phone is forever busy
like every asian tranny hooker

but i'd suggest stuffing in a portable miniature secretary phone instead, as it has all the circuitry and buttons already
>>
>>2989941
ill order the thing from aliexpress and hook it up, at worst i'll fry my modem
>>
>>2989938
Because a proper MPPT algorithm is a looping process. Measure voltage and current, multiply them together, and vary the duty-cycle until the product is maximised. Even without the seeking logic, multiplication like that is a pain to do analog.

I’ve seen some cheap mock-MPPT ICs, where you program in a maximum power voltage via resistive divider, and its feedback loop attempts to keep that constant. Might be 5% less efficient than a proper MPPT algorithm, but it’s much simpler and cheaper. It was a Chinese brand chip like this that I used.
>>
finished routing and attached the edge connector. I think this is looking better than my previous attempts. Tried to keep the jumps on the bottom layer as short as possible, it will otherwise be ground, +/- 12 V and +5 V
>>
>>2989999
I more or less didn't bother with ground fill on the top layer because there are so many traces that I end up with a lot of isolated areas. The back ground plane is fairly unbroken, though
thanks for reading my blog
>>
>>2990009
Stitching vias. Needs more stitching vias to cover the long traces going to the pin header.
>>
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>>2990009
>>2990017
Yeah I think either a bunch of stitching vias, or at least go out of your way to push the power traces to the very perimeter, like I've done here with the 5V rail. Such that no ground-referenced pads are outside them, ideally no signal traces either. R12, R67, etc. have a pretty roundabout return path.
>>
>>2990009
Also C25 is backwards, if it's polarised.
>>
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>>2990017
>>2990041
>>2990042
thanks anons, it's useful to be able to run these by people who know what they are doing. I tried harder to route the power traces and I think they break up the ground plane a lot less now?
>>
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What is this mystery pin?
I spotted a shiny thing on the carpet. It's not from any project of mine. I don't recognize this type of pin at all. It must have fell out of a device or appliance. I have no clue what though. Nothing around the house appears to be malfunctioning.
>>
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>>2990128
NEMA connector?
>>
>>2990131
Far too small.
0.4mm thick
13.88mm length
2.54mm at the wider part
1.41mm at the thinner part
Not magnetic at all.
>>
>>2990128
>>2990136
USB A contact?
>>
>>2990138
Looking closer, 2.54mm seems way to wide for that. It still looks like a connector from some sort of plug. Especially given the plating, wear, being non-ferrous, and the indent on the smaller side.
>>
>>2990062
Yeah that looks good. C29 looks a bit isolated, but it doesn't matter since the top-side ground-plane connects it to C24. It's not necessary anymore, but if you wanted to, you could run the traces from the pin-header to the THT caps on the top-side of the board, then run bottom-side traces from the THT caps to the rest of the board.
>>
>>2990142
I hope it won't matter too much because I just ordered the board, lel. At that point in the board the top layer ground plane leads right back to a ground, pin so I'm hoping it should be fine.
The boards were about 50 cents each for 10. I don't know how JLCPCB do it. I suppose they're subsidized by their government as part of a plan to achieve global dominance or something.
>>
Got hired by my friend to do a smart meter lora project for him for several buildings. This is great. I love doing shit like that, plus i can do it literally 10x cheaper than the cheapest commercial solution.
All those chinkshit parts i impulsepurchased from ali over the years and never used will finally come in handy. I have such a stock of them i don't even need to buy anything else kek
>>
>>2990179
Check the current prices for the things you need to replenish and include/mark up that cost in your invoice.
>>
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>>2989599
Which button do you need to press to turn on the LED?
>>
>>2990264
2 or 5
>>
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>>2990128
I figured it out. It's a placeholder for the analog ground on an HDMI to DVI-D cable.
>>
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>>2989757
For SMT caps, the lead is on the bottom J-lead. You don't want to tack the edges with an iron. You want the whole lead to be soldered to the board. Best for a hot air station work. See image.
>>
>>2990425
Flux and capillarity will cover the whole lead just fine as long as you have enough protruding pad to soak the heat
Don't want to heat caps too much
>>
>>2990425
>>2990427
interesting anon. I'm glad I decided to go with through-hole electrolytics though, they will probably be less painful to work with.
Just waiting for all the parts to arrive now......
>>
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>>2990062
Looks like its coming together nice.
Some points I have found for your consideration.
1 and 2: No right angles, the board manufacture may or may not have improved etching processes controls in place and its best to design your board to be manufactured from anyone. Etching chemical may pool in the corners and the trace may fail over time. Its just good manufacturing process to eliminate fail points for a process.
3. Now that you have used the grid to line up all your components, you can now break-it to line shit up.
4. You got the space here. Why are the traces bunched up? Move the bank of resistors north and force yourself here to have the bottom traces for the resistor start going south and fan it out nice.
Make it beautiful.
>>
>>2990427
One end for SMT caps is typically tied to a ground plane. ISO-fine for one time fix, ISO-not-so-fine for manufacturing.
>>
>>2990432
Thanks for the pointers, although I'll have to use them to inform future designs, as this board is already ordered.
I was dimly aware of the "90 degree corner etchant trap" concept, but is it really still a consideration in current year? My traces are 0.3 mm.

I see that one of those traces in area 4 goes uncomfortably close to a pad, but hopefully I can get away with it.
>>
>>2990435
From experience: First prototypes never make the cut for manufacturing. You have more knowledge now then when you started and best practices are best. Hunt down the IPC standard pdf files that have been posted on the net and learn from the process and manufacturing engineers experience from the past to make you a better designer.
Are you having a fun time doing this?
>>
>>2990432
>Etching chemical may pool in the corners
Never heard of that issue with any fab house, and even my own etched boards don't suffer from it.

>>2990434
Is roasting an electrolytic cap with hot air ISO-fine?

>>2990435
In future you can change your design rules to force larger clearances, might make avoiding situations like R34's pad 2 easier. In principle these should be changed to be at least as restrictive as your chosen fab-house, but I've never had any issues relating to fab house clearances.
>>
>>2990437
>Is roasting an electrolytic cap with hot air ISO-fine?
They are designed for hot air [re]flow ovens.
>>
>>2990436
This is only ever going to be a hand-soldered hobby project thing, but it will still make sense to look at the standards for future projects. I guess it is fun - although for one-off circuits, I'm still imagining that strip board and through hole components are my best option. But maybe I am living in the last century.

>>2990437
0.2 mm spacing between that pad and trace, but at least the trace will have the solder mask covering it...............
>>
>>2990439
>but at least the trace will have the solder mask covering it...............
This is where you need to know your board shops tolerances.
This passed my light-cones (eyes) today. Maybe something you would like.
https://hackaday.com/2026/05/12/another-gift-to-the-world-from-cern-their-entire-set-of-kicad-libraries/
https://gitlab.com/ohwr/cern-kicad-libs
Looks like 18k footprints library.
>>
>>2990441
Looks like I am in the clear, but I'll tweak my design rules settings anyway for next time.
Thanks for the link, 18k footprints sure is a lot.
>>
>>2990441
Cmon man, my package manager already takes like 5 minutes to confirm that there are no updates to my footprint, symbol, and 3d libs each.
>>
>>2990442
Now what is the tolerances for solder mask registration? Is there a chance the mask maybe offset from the pad that the trace is exposed? I'm not trying to be a dick. These are things for consideration when you manufacture boards. Good manufacturing practices.
>>
>>2990443
>5 minutes to confirm
Sounds like you got five minutes for games now. Your welcome.
>>
>>2990444
this is all useful stuff that I wasn't specifically aware of, so thanks. I can't actually find figures on the tolerance for the alignment, so I have decided to believe that it will be fine. Guess I'll find out when they arrive.
If it all turns out to be a disaster and that trace and pad somehow get connected, the only consequence is that I lose the use of 1 out of 8 board addresses, no big deal.
>>
>>2990447
No thank you. I had to leave a career in contract electronic manufacturing for personal moral reasons. I loved the work. Keep posting I would really like to see the progress.
>>
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>>2990425
>J-lead.
>>2990431
If you go down the SMT path, as you should, then definitely go for this type of a cap and not the through hole. If you're doing SMT, a soldering iron should not be your primary soldering tool.
When I do SMT, I always use a stencil. I can't even explain how much faster spreading solder with a stencil is vs. a soldering iron. Heck, sometimes it's OK to just squirt some paste out of syringe and spread it that way if you don't have a stencil.
Also, oftentimes you don't even need electrolytics and can get away with MLCC or tantalums.
tl;dr: if you're doing SMT, everything should be SMT including the electrolytics. That simplifies the BOM, cost, and speeds up assembly.
>>
>>2990520
Here is an AI blurb on esr.
The ESR values can vary significantly based on the type of capacitor:
Capacitor Type Typical ESR Range
Ceramic Capacitors 0.01 - 0.1 Ω
Aluminum Electrolytic Up to several Ω
Tantalum Capacitors Higher than ceramics

Understanding and managing ESR is essential for optimizing the performance and longevity of capacitors in electronic circuits.
>>
>>2990522
ESR is not that big of an issue in modern circuits if you know how to avoid oscillation and instability. Modern caps will outlive device's useful lifespan if you know how to manage the temp. Modern caps will easily do 10k hours at max temp. Orders of magnitude at lower operating ranges.
MLCCs almost always fail because they were soldered with a soldering iron or the board was flexing too much due to temp changes.
The reasons why you'd choose electrolytics over MLCCs or tantalums is the need for ca cap to operate at higher voltages, or you need higher capacitance or want to reduce cost.
PS: and don't use AI for this shit. Use your fucking head., Don't outsource thinking to a machine.
>>
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So how much should I trust these counterfeit Scyllac capacitors (normally $10k+ each) being sold for $1.50?
>>
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>>2990537
Even less than the ebay sellers quoting $120 for an m4 mac mini.
>>
>>2990524
>device's useful lifespan
We come from a different school of thought. Your being a dick. I don't outsource thinking to AI. I'm just not investing time-energy into replying to you for your shitty attitude.
>>
>>2990576
>shitty attitude
Says a guy who using an AI to craft responses and when he's proven wrong, he claims the other guy is being a dick and has a shitty attitude. Your attitude sucks and that's why you know so little.
>>
>>2990520
If you’ve got stencils and hot air, you’re probably right. But I think this anon is stuck with a soldering iron, also stencils are kinda expensive. To the point where it’s cheaper to get them to solder the components on for you.

>>2990524
MLCCs also have a distinct voltage dependence to their capacitance to watch out for. And microphonic behaviour. Electrolytics don’t have that. But you wouldn’t catch me dead using a tant.

>>2990576
You posted shit about ESR unprompted, nobody asked about ESR in the first place. Why would you go out of your way to do that?
>>
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>>2990613
>If you’ve got stencils and hot air, you’re probably right. But I think this anon is stuck with a soldering iron, also stencils are kinda expensive. To the point where it’s cheaper to get them to solder the components on for you.

NTA but you don't even need hot air. You can do it with a cheap hotplate. I've used a syringe to dispense solder paste onto pads and have placed components with tweezers. Surface tension just pulls all of the components in place and I rarely had bridges or soldering failures.

Hot plate element is like $15 (or less) and you need a temp PID controller or even better, an Arduino, so you can program the temperature ramps.

Soldering SMD with an iron is not only slow but also damages components.
>>
>>2990615
isn't it difficult to get the entire surface to heat up uniformly without hot spots?
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>>2990615
>cheap hotplate
Eh, if you're doing SOICs and 0805s and don't have stencils, I think I'd rather use an iron. Hand-dispensed solder paste would be worth considering if it were a bunch of 0402s, or DFNs or other leadless chips. Number of parts is another factor of course.
>Hot plate element is like $15 (or less) and you need a temp PID controller
Looked into this myself, those hotplates have a PTC heating element, so an off-the-shelf PID controller won't work very well. PID algorithms assume the input duty-cycle will produce a proportional dT/dt regardless of state temperature, but here that proportionality constant changes significantly as a function of state temperature. I expect you'd end up with a very sluggish system, but it might still be fast enough for normal reflow curves. With an arduino you'd be able to use a PID algorithm followed by a correction equation/lookup table.

Even cheaper and easier would be to manually control the temperature with a TRIAC dimmer while watching a thermocouple. Going blindly open-loop probably wouldn't be the end of the world either. Not like manual hot-air reflowing follows a proper cooling curve.

>Soldering SMD with an iron is not only slow but also damages components
Source? Seems like using an iron can be significantly quicker, putting less heat into the components. I can't imagine the thermal expansion/contraction of components is a sufficient factor unless you're somehow blasting heat into the component but not the board. MLCCs seem the most likely to break from thermal stress, but even then they're designed to handle some amount of it. Never had a hand-soldered MLCC break on me in my years of hand-soldering 0805s and 0603s.
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>>2990624
>isn't it difficult to get the entire surface to heat up uniformly without hot spots?

No, they're made to be uniform. You can find pictures of people testing them with a thermal camera.

If you want to go third-world, a clothes iron with an arduino can also work. There's so many people showing this method online (YT, Instructables etc).
>>
endless options on AliExpress to burn your house down, it seems.
Why on earth do they make USB-powered hot plates, that seems like a lot of juice to pull through a USB connection
>>
>>2990439
>at least the trace will have the solder mask covering it.
Just FYI, solder mask is incidentally an insulator (bonus!) but is not intended as one and should not be used deliberately as one. Safety standards are explicit about this, but it's best to consider it a general principle even if you're not going to be going through that kind of evaluation.
>>
>>2990643
The USB ones I've seen before are very small, 5x5cm sort of thing. On a 65W PD supply that's slow, but not completely unreasonable. Those Alientek ones are bigger (104x64mm), but they can do 140W PD and 200W from DC, and claims 120s heat up time to 260C.

I was going to make my own reflow plate, since there is a big price difference between the little PTC hotplates you wire up yourself and those. But taking a closer look, these things solve a lot of the problems that are difficult to solve with a soldering iron and a 3D printer, namely the heat resistant housing. House fires aren't really a risk considering you turn these things on, use them for 5-20 minutes, then turn them off again. Not like a 3D printer that you leave for hours unsupervised. My only problems are as follows:
- Lots of them say they're for preheating, and alientek claims many other hotplates only go up to 260C, so may struggle reflowing a board on their own.
- Most of the reflow plates look to use simple temperature setting interfaces, which are likely constant temperature regulators, instead of temperature-time curve controllers.
- Why do I have to buy two different hotplates for soldering and chemistry, can I not get a 350C hotplate with magnetic stirring?
And now I'm back to thinking I should make one or modify one. I guess adding magnetic stirring to a soldering hotplate is easier than the alternative. Assuming the hotplate itself isn't magnetic.
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>>2990643
>endless options on AliExpress to burn your house down, it seems.
They ship tens of thousands of those and how many houses burn down from them?
>Why on earth do they make USB-powered hot plates, that seems like a lot of juice to pull through a USB connection
because USB-C PD exists and you can do a fair bit with 240W? But yeah, I'd prefer something around 400W.
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>>2990712
hmmmm

>>2990714
Even then I've never seen any 56V 5A soldering hardware, only ever 20V/28V 5A or lower.
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>>2990643
>endless options on AliExpress to burn your house down
you preheating these things then going for a nuggie run?
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>>2990633
Haha… using an iron for everything was common practice in the 70s and 80s. If we had to put ends on a bunch of phono plugs we’d put them in the steam holes on the bottom of the iron and start tinning.
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>>2990585
Ya i don't keep the scale for esr in memory by capacitor type. I worked in medicine and engineering without a degree for I am competent.
EAT DICK FAGGOT.
>>
You lack comprehension for the post thread.
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>>2990712
>only go up to 260C
isn't there something to be said for low temperature solder for hobby projects though?

Sn42/Bi57.6/Ag0.4 allegedly melts at about 140 C

https://cpc.farnell.com/chip-quik/ts391lt/solder-paste-low-temp-15g/dp/SD02706
>>
>>2990643
I am tempted. Even if it's not very good it will let me recover $20 worth of ICs from other boards that I messed up in the past
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>>2990842
I’ve used it before, it solders nice. But it’s also somewhat weaker, much less common, and forms very brittle joints when mixed with leaded solder. Also not very useful for existing boards without special flavour solder.
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>>2990850
I'll have to look up review videos of these. Because they just regulate for a constant temperature, unlike the smarter anemic USB models.
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Use case?
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>>2990906
they can be used to replace Compton valves in older designs
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Why is my solder being outright repelled by my iron?
>clean ur tip
I've used tip cleaner and flux and it hasn't made any difference.
>>
>>2991156
>used tip cleaner and flux

completely inadequate for the situation
to get rid of the black crud, you scrape it with the back side of an x-acto knife, or box cutter
as soon as you see a hint of shininess, apply solder to tin it
keep going around until the tip front is all shiny and chrome
>>
>>2991156
If a good hard scrub (with something no harder than copper) doesn't bring back a tinnable surface, your plating is probably fucked. But I'd guess it's just too much crud. I find a scrub with a facial tissue or paper-towel (while hot) often works where copper wool doesn't.
Citric acid powder might also work, idk.
>>
>>2991156
When you get a new tip, tin it and clean it a few times before you use it. Keep it clean while you work, and load the tip with a fresh blob of solder before you turn it off. Only use RMA flux and leaded 60/40 or 63/37 solder with your iron, and keep the iron at a moderate temperature.
>>
>>2991156
If the plating is really gone, tip cleaner will not help, and you will need a new tip. Tip cleaner is very aggressive and you should only use it in last-ditch maybe-I-can-rescue-this situations like, well, that black tip that won't take tinning for love or money. If it doesn't work you need a new tip.

If you have used plumbing flux on the tip, it can completely destroy the plating. That's just one of many reasons soldering with flux is at least intermediate-level. Because you can choose the wrong flux.
>>
>>2991156
>>2991178
>keep the iron at a moderate temperature
I would be more explicit and say to keep it at the lowest temperature practicable. Hot tips get eaten by oxidation and burn off flux way too quickly.
>>
>>2991156
Scrub off the junk and hope the plating isn't fucked. If the plating is damaged, the tip is effectively dead and it will erode very fast.
Always clean the tip properly (use brass wool, NOT steel wool - check with a magnet to test for counterfeits) and keep it tinned to prolong the life. Properly cared for, a tip can last years with daily use.
May be worth looking into tip care, they generally don't go bad like that unless you're doing something to damage it. Using overly aggressive fluxes, leaving it untinned (especially at high temperatures), or scraping with something abrasive can all very quickly degrade it.
>>
>>2989599
Why is a diode needed on the relay here?
>>
>>2991279
To prevent the inductive effect caused by the relay, so the reverse flowing current wont damage the transistor
>>
Does anyone have some suggestions for some projects I could do to improve my my ability?

I started an avionics apprenticeship a few months ago and I'm learning but slowly and I need my hand held most of the time. Would like to try and get better on my own but I'm not much of a self starter and don't know where to start.
>>
>>2991290
What exactly is it you want to train by making a project?
>your ability to design circuit schematics
>your ability to lay out circuits on a PCB or protoboard
>your ability to solder and assemble circuits
>your ability to test and troubleshoot circuits
Or something else?
And what fields are you specifically trying to learn, I don't know shit about avionics.

Here's some lists of projects:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png
https://github.com/74HC14/ohmOP/blob/main/ProjectCategories.md
But some are "follow the instructions" type challenges, others are "design X from scratch" type challenges, with various stages in between. To some extent, the projects you build can be useful, especially instrumentation projects like a milliohm meter or a capacitor/inductor ring-tester.
>>
>>2991295
Well in my job I've gotta make/repair a lot of wiring looms and troubleshoot components/circuits, interpret wiring diagrams.
I've got a bit of practice putting together looms now though I'm hardly a pro. Probably learning to understand how they work would be the most useful thing for me.

For instance, the other day I was given this device, not sure what you call it but you plugged your headset in and 3 position switch to transmit on intercom and a radio PTT button, and I had to work out what all the wires were doing so I could alter these other ones that had a volume knob instead of the button.

Anyway I'll take a look at the projects, thanks. Building useful stuff always appeals to me.
>>
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>>2989599
how would i do pic related? it doesn't matter if it's edge or level triggered.

>CLK is 200 khz, variable duty cycle
>OUT gets triggered "on" with high CLK
>OUT gets triggered "off" with low CLK (OR) high RST
>if OUT is triggered "off" it remains "off" until the next high CLK
>RST can be ignored with low CLK

the basic component would be a reset dominant SR latch, where CLK=S and RST=R. but i'm not understanding how to get the RST event to latch OUT "off" until the next positive CLK cycle.
>>
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hey guys, I need some help with USB stuff
I have a charging dock for my Dualsense, it just needs usb c power
I also recently started using a pi pico 2 W as a dongle for it on my PC (https://github.com/awalol/DS5Dongle), and I would like to be able to "integrate" it with the charging dock, so I could use both from a single usb cable going to the pc.
obviously the simple answer is a usb hub, but I wanted to know if I can "tap into" the usb-c connection of the charging dock, since that only uses usb-c for power and not data.
if it requires adding a few components and not just wiring, that would be fine too.
thanks in advance
>>
>>2991351
Just split it off of the charger PCB, or use a type C splitter cable with a type C to micro USB adapter on the Pico. There are other options too.
>>
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making an extruder board for my 3D printer.
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>>2991389
Cool stuff. What’s the motivation behind a custom board?
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>>2991402
I want to replace the OEM main board with an off the shelf part and making custom CAN tool head board is the least janky way to do it.
>>
Just found rbdimmer.com, they sell a couple of TRIAC dimmer modules that are controlled via UART or I2C, which makes it nice and easy to drive a load without worrying about zero-crossing synchronicity. But the 8A module has awful LV/HV isolation so I’d only ever go for the 4A. Especially good for non-real-time control from a computer or raspberry pi or whatever.
>>
>>2991404
What off the shelf part do you need it to work with? Some sort of bed level sensor or accelerometer?
>>
>>2991406
I have a Manta m5p with a CM4 I want to install, the SOC the OEM used is barely adequate for the application. the CM4 might have enough UART's to connect everything but I also want to add a few things to the tool head, plus the printer is littered with Chinese STM32 knockoff parts that makes running main line klipper problematic, if the tool head board works out then I'll make a custom CAN load cell board also.
>>
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Alright, very cheap and questionably safe AliExpress hot plate is en route, do any anons have recommendations for solder paste for SMT boards? I don't have a stencil made, so I plan to just dispense from a syringe.
A buddy recommended the low-melting Sn42/Bi57.6/Ag0.4 but I'm sure there are other factors to consider besides just melting point.
If my calculations are correct, then everything here except the Pi will fit on my ~100 x 80 mm board.
>>
>>2991412
Oh the printer didn’t originally have a toolhead board. How does your board compare to other toolhead boards?
>>
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Ignition control board

1/3
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>>2991428
Ignition control board

2/3
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>>2991426
I'm using the schematic for the EBB36 as a guide so it's an EBB36 in a form factor to fit my printer.

https://github.com/bigtreetech/EBB
>>
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>>2991429
Ignition control board

3/3

Soviet ICs were used
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>>2991428
Wow, EPROM in a real project is cool. What kind of work does it do, just timing control?
>>
I really want to buy an oscilloscope but don't want to spend 200-300$ on something I don't know how many times, how often I would use
I'm getting into electronics, I want to learn embedded and circuit design as a hobby and not necessarily a job; ESP32 programming, analog audio circuits and processing, repairing things that break at home maybe too
do I hunt for a locally sourced 30eur old analog oscilloscope, or get a digital one? I think I'd get more use out of something I can connect to a PC, to also be able to look at the data more comfortably, collect it and run algorithms and analysis and whatever I'd like, but I don't know if a USB oscilloscope is a good idea, and if a cheap one has the necessary safety features, I don't want to kill both the scope and my PC
also, I'm in EU



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