/ohm/ - Electronics General: toroid winding edition

[Anonymous No.2709490]

Thread reworked:>>2701116

>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.2709616]

>>2709490
I would love to build a distributed system counting people going in and out of rooms, maybe by sensing capacitance or something.

Rolling on that list of challenges instead, because I've never done a solo project before.

[Anonymous No.2709668]

>>2707659
Anon from last thread here, i just did my homeworkand if i see this right it goes something like this? So the cutoff in this “filter” would be defined by the size of the vibrating area, let’s say a smol round piezo buzzer, the diameter of this should be the length of the standing wave, no? Then the cutoff frequency F follows from the diameter of the piezo D and the propagation speed of sound in quartz crystal v as F= D/v amirite? I tried to figure it out without googling too much but this should be the basic right?

[Anonymous No.2709689]

>>2709668
Generate a frequency sweep and look at the receiving disc's waveform on a scope.

[Anonymous No.2709765]

>>2709689
>hey guys i have this tank, to calculate the volume i just do x*y*z rite?
>just fill it with water and count the liters bro

[Anonymous No.2709779]

>>2709765
>manually cutting piezo buzzer discs
>why are my calculations so far off
Also the wavelength is pretty long.

[Anonymous No.2709786]

>>2709668
The lowest mode of a circle needs Bessel function to calculate (just google it) but otherwise yeah, you really want to measure it though

[Anonymous No.2710012]

>Bored Ape NFT event attendees report ‘severe eye burn’ from UVC bulbs used at the venue
wasn't there some faggot from two threads ago who wanted to do this as a "prank?"

[Anonymous No.2710013]

>>2709490
nice cockring collection OP

[Anonymous No.2710063]

>>2709490
anyone ever try making a hybrid topology smps --> linear post-regulator c/cv power supply? i want to make a general purpose lab power supply with quad outputs (floating +/- 30V @ 3A) but i definitely do not want to deal with buying multiple 100VA toroidal transformers, designing an enclosure, etc.

[Anonymous No.2710114]

>>2709616
I one thought of using old xbox kinects for something like that.

[Anonymous No.2710136]

>>2710114
>I one thought of using old xbox kinects

me too.
i suspect many young maker types dream of growing up and doing something really world-changing, like counting people in a room.

[Anonymous No.2710137]

i am using tp4056 board to charge a lipo battery and when the battery is near being full it starts making a high pitched whistling noise, the 4056 i mean, is that normal?

[Anonymous No.2710165]

>>2710136
At class a proff was demonstrating a cookie chocolate chip counting routine. He placed a cookie in front of the cam. Display indicated 7. He went on to explain the vision algorithm as a fly landed on the cookie. Display updated to 8. Hilarity ensued. BTW every tenth cookie in commercially produced cookies has 2x chips as he demonstrated with the machine and a freshly opened bag of Ahoy type cookies. You see the one bulging with chips and the chimp part of your brain thinks "wow, must be these are all really full of ones I just can't see!". Food co's are insidious.

[Anonymous No.2710207]

>>2710165
this post gave me indigestion and heartburn

[Anonymous No.2710217]

>>2710165
>every tenth cookie in commercially produced cookies has 2x chips as he demonstrated with the machine and a freshly opened bag of Ahoy type cookies
This post got me thinkin' about those beans.

[Anonymous No.2710268]

>>2710165
Yeah, well, the chocolate chips are also just on the top. Which isn’t too bad, but for muffins it’s the same. You’re brain is thinking “those chips are probably evenly distributed throughout the substrate evenly” but, no.

I saw a paper on companies and the amount of time/effort/money they spend on their core business. They found that companies spend the most on trying to rip-off and scam their own customers nowadays.

[Anonymous No.2710271]

>>2710012
Yeah, now they’re probably gonna ban UV lamps along with peaceful protests, green lasers, birth control, dado blades, body armor, and RC drones.

[Anonymous No.2710278]

>>2710137
Yeah, it’s just the oscillations of the inverter trying to pump it with electrons.
Anything above 80% charge is into the law of dimishing returns—follow the min 20% max 80% rule and you’ll be fine.
If you want your battery to last, trickle charge it whenever you can, instead of quick charging it, and don’t leave it in the charger.
Wireless phones and other similar devices have an initial charge of 19 hours when you buy a new one.

[Anonymous No.2710333]

>>2710137
There’s nothing there that should be vibrating (e.g. an inductor making coil-whine). Either it’s a dodgy capacitor (doubt) or the lipo itself is making noise (scary). I can’t imagine the IC itself making noise unless it’s getting real hot and vaporising some flux or water stuck under it.

[Anonymous No.2710347]

>>2710137
What are you powering it with?

[Anonymous No.2710406]

I have a pair of bluetooth headphones that I'd like to attach an aux cable to so it can work without batteries.

Is it as simple simple as soldering an aux cable to the headphones speakers?

[Anonymous No.2710414]

My stm32 not connecting mystery is fixed. the issue was really quite simple: I'm a no good dumbdumb poopy head and connected the wires in the wrong order.

Can someone explain to me why /ohm/ was so much more helpful and knowledgeable about this than /mcg/ though?

[Anonymous No.2710422]

>>2710414
>Can someone explain to me why /ohm/ was so much more helpful and knowledgeable about this than /mcg/ though?

probably cause you a dumbass.

[Anonymous No.2710423]

>>2710422
Sounds like backward logic to me, but what do I know, I AM a dumbass after all.

[Anonymous No.2710432]

>>2710423
Hey I'm a dumbass too. Nice to meet ya, fellow dumbass.

[Anonymous No.2710435]

>>2710432
High-five, fellow dumbass. Always nice to see a senior to show the way.

[Anonymous No.2710441]

>>2710435
Everybody says "you dumbass" but nobody ever says "can i help you dumbass". Probably because they're dumbasses.

[Anonymous No.2710442]

>>2710406
> Is it as simple simple as soldering an aux cable to the headphones speakers?
Only if the speakers are sensitive enough to operate without an amplifier. Hard to say on this one. Might be able to get away without an amp, maybe using an impedance changing transformer.
Personally I’d add a switch so the audio signal isn’t being fed into the output of the amplifier, could cause funny shit otherwise. A switched headphone jack might be able to do that for you.

>>2710414
Because you had a wiring problem, not a firmware problem. It was impossible to know which problem you had before you fixed it, unless you actually double checked the wiring, so it was a shot in the dark either way. But if you wanted an argument about little-vs-big endianness or RISC-V and Pine64 shitposting, you’d be better off on /mcg/ any day of the week.

[Anonymous No.2710447]

I finished up learning analog systems including circuit analysis up to op-amps and transistors. But when I try to find resources to translate this so building some digital embedded systems, it just seems to jump to "here buy this dev board and we'll interface with it over UART". Seems like a big leap. Am I missing something? How would I even build a system to power a board like the ones they want me to buy? Or how do I even think about clocks and crystals when I want to build my own system?

[Anonymous No.2710448]

>>2710442
>But if you wanted an argument about little-vs-big endianness or RISC-V and Pine64 shitposting, you’d be better off on /mcg/ any day of the week.
OK, so I guess /mcg/ is completely useless to me since I've got that part well under control. My issues will virtually always be /ohm/ related only I guess.

[Anonymous No.2710527]

Anyone know of a good lecture video series that I could watch in conjunction with reading The Art of Electronics?
I feel like I'm getting a grasp of the basics, but it would be good to see more examples and explanations to make sure I'm understanding it correctly.

[Anonymous No.2710579]

>>2710447
Look up the specs you need, draft up a list of possible parts to use, and catalogue their upsides and downsides. For microcontrollers a big part is what kind of software and programming hardware you have to use, but also the number of peripheral components required. Some chips need external program memory and/or crystals, some need nothing more than a bypass capacitor. See /mcg/ for a nuanced discussion and shitflinging over what programming environments are acceptable. You’ll probably end up going for whatever is popular, like STM32s or AVRs or whatever as these have the most support and existing documentation, but maybe you’ll have to go for something more obscure. PICs are only used by boomers.
Once you’ve chosen a chip, there should be adequate information in the chip’s datasheet and accompanying application notes to help you design a board from the ground up. Don’t be afraid to look up schematics of dev-boards either, sometimes they’re full of nonsense but they can have neat tricks like for powering off multiple power supplies without backfeeding.

[Anonymous No.2710624]

>>2710414
mcg is less active it half the time it devolves into some argument between x and y things

[Anonymous No.2710686]

Where are you guys buying BMS's from?
I need a bunch of different ones, and there's loads of companies offering them.

I'm trying to build something proper though, so I want something that's not shoddy crap.

[Anonymous No.2710694]

I have ESD boots for work, but do I need ESD insoles? Or can I throw any insole I want in?
>Why aren't you asking the QA Engineer?
Because he refuses to fucking answer

[Anonymous No.2710724]

without coping by just drawing something in ltspice, is there a way to understand how "complex" bjt circuits work, by reasoning through them? e.g. pic related is some sort of a feedback circuit, but i have no idea how it actually works. i've read about basic bjt configurations like common base/collector/emitter, and i can recognize building blocks like current mirorrs or darlington arrangements, but i don't understand how to connect these all together and discern what a circuit does.

[Anonymous No.2710736]

>>2709616
You can add a clicker for the door, very simple and reliable.
Mythbusters did this: https://youtu.be/c3LRJHmO794?t=21s

[Anonymous No.2710746]

>>2710724
It's all about approximations - a fundamental principle of engineering. You start by chopping up the circuit into functional blocks that you then represent with a simple mathematical approximation. Once you've identified the blocks, then you can connect them together and introduce feedback. If you want to really start understanding things you can watch
>https://www.youtube.com/watch?v=403CnTftB4M&list=PLc7Gz02Znph-c2-ssFpRrzYwbzplXfXUT
Analog electronics requires patience and good understanding of fundamental knowledge. There are no shortcuts, you just have to do a lot of it and eventually you will understand it. That's also the reason why it's less popular than programming or software as far as hobby work goes. Initial learning curve is an intimidating cliff that seems completely unapproachable.

[Anonymous No.2710776]

>>2710724
I mean, there's a reason that software like spice exists. Once you move past DC into time domain all the calculations get complex, and the graphing/visualization is just as tedious to create. Like the anon says, you break the circuit into parts. The EE's I knew from school moved everything into spice once anything more complex that Circuits 101 was done.
>>2710746
>That's also the reason why it's less popular than programming or software as far as hobby work goes.
Well, that and the SW end has become incredibly cheap and accessible, and from an industry standpoint, SW changes are much easier than HW if you need to tweak things in production.
Example: I did a blinky LED circuit for some halloween stuff using a 555. Was trying to figure out how to do flicker on 3 LEDs, and looked up some circuits... realized it would be cheaper/faster to code an arduino to do it that build a custom circuit from scratch.

[Anonymous No.2710784]

>>2710776
For artistic things analog has some qualities that might make it more desirable compared to digital system. Analog behaves like a living breathing organism that reacts to its environment. Digital is very robotic and precise. For your blinky example you approached it with digital mindset, so of course it's better suited for arduino implementation. Analog way would involve thinking from signal perspective and then applying transforms on that signal. You could have started with noise generator and filtered it to desired frequency to then use it to modulate LED current. Or maybe start with a chaotic system and then use that signal as main starting point. It is a bit more work, but in my opinion reward is a lot greater compared to just writing some code and clicking upload.

[Anonymous No.2710996]

>>2710063
>a hybrid topology smps
I haven't made one, but it is definitely on my to-do list. It would be a split-H boost-buck topology running off a 12V ATX PSU. That topology is nice for having continuous input and output current. The ATX also gives me a nice -12V rail for analogue circuitry. I want to use a pair of TL494s since the CC/CV is nice and easy, using MCU-controlled DACs as the voltage and current references. But I'm not really sure how the buck and boost stages would interact with one another, I may be best off just using a microcontroller as the PWM controller.

The linear post-regulator would be an array of parallel Sziklai pairs, maybe IGBTs. An easy method is just to use capacitance multipliers for good ripple rejection and a low voltage drop and no extra feedback loop, but I'm not sure if it's the best way to go. Using PNP pass transistors would let me get much lower voltage drop, but the ripple rejection and loop stability will be worse.

Personally I'll just be making a single-rail supply. For audio uses I don't need variable voltage so I just use a transformer-based PSU.

[Anonymous No.2711019]

>>2710996
ive thought about using an ATX power supply as well but my thought was that you might get competing SMPS control loops interacting in a bad way. im thinking offline flyback to within a few volts of the linear post-regulator might give me the best stability overall. im not doing anything super precise, just looking for a reasonably "low ripple" DIY hybrid linear power supply, lower ripple than a switcher alone.

[Anonymous No.2711190]

>>2711019
>you might get competing SMPS control loops interacting in a bad way
Not a problem so long as your converter has continuous current at the input. Even with discontinuous current it's probably fine, you can just add some LC filtration if you absolutely need to.
>offline flyback
That method has always repelled me. If I use a dedicated off-line switching converter, I'm not necessarily getting efficient switching (e.g. I can't use a gate driver IC and synchronous switching), and adjusting the feedback loop for a variable voltage all the way down to 0V would probably be impossible. If I use an IC like the TL494 or an MCU I can get much more control over the switching circuit, but bootstrapping becomes a massive pain.
Either way there's the magnetics to worry about, you need a transformer with an air gap and the right inductance ratio to be efficient. I've no idea how to classify a flyback transformer, I'm guessing it can be modelled as a conventional transformer but with significant uncoupled inductance on the primary and secondary, but I don't get that kind of data from the datasheets I read.

Push-pull isolated off-line converters don't need this air-gap and so are certainly simpler.

If you don't care about voltage being too precise you can just add an open-loop capacitance multiplier and it will get rid of a huge amount of your SMPS ripple. A BJT zener regulator with a big capacitor across the zener is going to be even better, and using a TL431 instead of a zener will make it more precise. I'd go this way if you're just making a fixed-voltage PSU, and can get an existing SMPS with a voltage you're fine being ~2V below.

[Anonymous No.2711258]

henlo, frens.
i posted this on /csg/ (didn't roll 9 btw, came straight from /g/)
yesterday, but has just now realized the project may also interest /diy/:
>>>/g/97276664
>>>/g/97276678
after comments in the thread and further thoughts, i'm also
>replacing ATMega328P's with ESP32-C3's
>replacing it 74HC595's and SN74141's with HV5222's
t. picrel's what the pcb will end up looking like but with much larger tubes

[Anonymous No.2711331]

Oliver Heaviside talks such wicked mad shit in "Electromagnetic Theory", it's incredible. The entire book is 50% unparalleled insight into EM theory, with the other 50% him shitting all over mathematicians, detractors of the theory, germans, and the english

[Anonymous No.2711335]

>>2711258
why would you replace the atmegas with esp32s

[Anonymous No.2711338]

>>2711335
Different Anon, but prolly to get the time from the innernets and/or remote detonation.

[Anonymous No.2711344]

>>2711258
>>2711335
>>2711338
I see, it's a nixie clock. I see the person in the /g/ thread suggesting it can update its time automatically from the internet. I guess that's about the only good/legit use case for an esp32 in this case; otherwise I was about to start dunking

[Anonymous No.2711373]

>>2711338
>>2711344
>not using a gps receiver or radio time signal for time synchronisation
ngmi

[Anonymous No.2711383]

which socket to use with the edge connectors of these protoboards?

[Anonymous No.2711384]

Could you guys recommend me a connector?

I’m looking for a 24VDC connector, 4A max that is available both inline (both male and female) as well as a female surface mounted receptacle.

All I can find are either 12v/18v/2a rated, or not available in all three forms. Something like related would be ideal but in 24v 2a

[Anonymous No.2711387]

How can you make money as an electronics hobbyist? I'm trying to get some hand on experience to put the things I learn in school to practice while also making some money on the side.
Repairing broken electronics and disassembling/selling parts comes to mind, but not much else..

pic unrelated.

[Anonymous No.2711395]

>>2711384
as long as you're not selling it to NASA or the military, I guarantee you a 12 v connector can handle 24 volts. I'd get the right current rating or higher.

[Anonymous No.2711411]

>>2711335
>>2711338
>>2711344
>>2711373
>>2711394
>>2711387
i asked my HDD repair guy what software he used in the report he screencapped me and i went down a long rabbit-hole on HDD repair. repair tooling software is expensive as fuck and you also need to attend a workshop with them but HDD repair is good money, brother, much better than tech support. you'll get $300+ per salvage as well as an endless stream of customers bc consumer HDD (official stores, Amazon, brick-and-mortar Micro Center, etc.) are unreliable af while all the reliable shit get sent to data centers.
pro-tip from the guy: when buying HDD, buy robust ones made for the industry. don't buy faggy shit like ones made for creators, gamers, or home-use.

[Anonymous No.2711417]

>>2711383
>which socket

it's called a card edge connector.
specify spacing between pins, and number of pins.

[Anonymous No.2711419]

>>2711417

and also pcb thickness.
dont want things to be loose, like yr mom.

[Anonymous No.2711420]

>>2711383
this is the closest I've found but it is unclear how it is fastened (through-hole etc)

[Anonymous No.2711428]

>>2711417
>card edge connector
Ah the magic keywords, thanks! I'm planning expansion slots to a DIY synth for effects and whatnot. Just an experimental toy so screw the eurorack standards.

[Anonymous No.2711433]

>>2711428
>the magic keywords

another magic word of interest is 'card cage'

[Anonymous No.2711434]

>>2711383
That's not an edge connector. Those are wire pads but you can use them for SMD LEDs and various shit. They aren't connected to anything, just floating pads.

[Anonymous No.2711436]

>>2711434
This
The pad will be too deep in an edge connector to be useful. Anything soldered there will fuck the connector. It's just a pad and it's certainly not rated for insertions.

[Anonymous No.2711438]

>>2711384
XT30/60/90

[Anonymous No.2711439]

>>2711387
How can you save money as a hobbyist? That's the right question. If you wanna make money, be an engineer and work for the man.

[Anonymous No.2711530]

>>2711387
Hifi stuff, especially with old systems owned by boomers and gen-xers. Be it repairing them for a customer, refurbishing them from thrift stores, or modding them to have Bluetooth or Alexa controls or RGBs or whatever. Could be as simple as adding an off-the-shelf TOSLINK decoder, USB sound-card, or HDMI audio extractor inside the enclosure or inside a seperate but aesthetically consistent enclosure. Repackaging existing equipment in different enclosure to suit a certain aesthetic feels like money to me, but that’s not really electronics.

You could also make and sell those Tech Ingredients panel exciter speakers, or do hifi call-outs to fix people’s ground loops or room EQ or shitty acoustics.

You can also offer custom circuit design. I did this once, while it was a fun and educational experience, it was pretty stressful trying to meet a deadline atop my error-filled PCB. I think you’re better off trying to make a general-purpose product (e.g. an MCU on a board with a few high-current half-bridges and a bunch of generic inputs) that you can program for a variety of customer use-cases. Demographics here are independent farmers and contractors, and also some industrial uses where they need some strange custom solution that doesn’t exist elsewhere.

[Anonymous No.2711563]

>>2711434
>>2711436
noted

[Anonymous No.2711570]

>>2709490
Hi guys. Working on a project to adapt a motion sim driver loaded Arduino to drive proportional hydraulic control PLCs instead. The arduino is set up to drive H-bridges as in pic. Instead, I need it to PWM either 0-5V analog or a drive circuit to directly drive the -10V to +10V PLCs. I know fixing it in the driver software would be more ideal but I'm even more incompetent with software than hardware. Can anyone scratch something up for me to adapt H-bridge pwm drive to a single voltage? I have a circuit to bring 0-5V up to -10 to +10 already and can build a gang of 3 of those easily. Appreciate it if anyone can come up with some solution!

[Anonymous No.2711574]

>>2711570
Someone here just did that like 1-4 weeks ago. Search through previous threads for “-10V” and you should see the op-amp circuits that were used.

[Anonymous No.2711584]

>>2711570
*Solution can involve the H-bridge sub boards, I have those as well. I just don't know how to make them work with a fixed ground and single voltage output.

[Anonymous No.2711586]

>>2711574
That was me, I still have one proto'd up and tested good on the bench. The problem now is driving it off the arduino's h-bridge pwm drive.

[Anonymous No.2711632]

>>2711586
Filter the PWM into DC using an RC filter? I don’t remember the op-amp circuit, but if it’s non-inverting then you can cascade quite a few of these passive filters (of increasing impedance) to create a sharper cutoff.

[Anonymous No.2711649]

Got my first soldering iron, something I should have done & wanted to for like 10 years. I plan on working on: laptop charger port, lithium battery replacement on an old music keyboard, and some capacitors on a few things. Any tips? How should I prep? Do I need a desoldering gun?

[Anonymous No.2711709]

>>2711632
Yes I was planning to do that with a resistor to a cap as you suggest. The problem is the H bridge output from the Arduino has a Righthand Spin Enable, Lefthand Spin Enable then Positive PWM and Negative PWM. I need a single line that outputs 0-5V or -10V to +10V out of it instead, that's what the PLC needs..

[Anonymous No.2711712]

>>2711709
*Perhaps if I were to RC smooth all six (that is, PWM righthand and PWM left hand per channel) then invert, say, all the left hand through an op-amp, then fed the total voltage right channel and left channel to another op amp... At this point I'd be dealing with a 0-10V range that would need to be bumped to -10 to +10. Hm.

[Anonymous No.2711713]

>>2711649
Iron's fine. View some youtube vids on soldering technique first, practice on a junk pcb a little, and watching a few repair vids like Shango066 is a good idea too. Good luck and remember, batteries and live power get very angry if shorted out.

[Anonymous No.2711726]

>>2711417
Can you actually find these for generic sizes? Last time I looked there were only ones available for the common motherboard slot sizes. I couldn't get one with 6 pins to use as an ICSP header, for example.

>>2711709
So when "Positive PWM" is 100% you want the output to be +10V, when "Negative PWM" is 100% you want the output to be -10V, and when they're both 0% you want the output to be 0V? What I'd do is feed the "Negative PWM" signal through a logical inverter, then combine it via resistor with the "Positive PWM" signal and filter the sum. You can also sum the outputs of two filters, but that's more components. If the PWM signals can both be on at the same time then you may get some funky timing artefacts that means you have to sum two filters. Consider taking the voltages not from the inputs to the H-bridges but from their outputs, it may allow you to avoid the use of a logical inverter.

[Anonymous No.2711743]

How does impedance matching work specifically in CAN transmission lines?
>signal travels through 120 ohm transmission line and hits a receiver with a different input impedance
>reflection happens
>add a 120ohm resistor in parallel
>signal reflection gets absorbed
Why?

[Anonymous No.2711745]

>>2711743
Signal is an EM wave and transmission/reflection applies. Reflections occur when there are impedance discontinuities. If you pick a correct resistor then from signals point of view no change of impedance occurred and wave just gets absorbed by resistor. For electrical circuits it might help to focus on power rather than voltages/currents. If you send 1W through a transmission line, but load can only eat 0.5W rest of the power has to go somewhere and it reflects back.

[Anonymous No.2711753]

>>2710063
>hybrid topology smps
Depends what designing means to you. You can easily grab an off the shelf SMPS and put linear regulators on the output and be done with it.
I've never designed a multi channel "high" power smps, only single channel and multi channel capable of a couple watts output.
A cool design would be a 4 channel variable output converter that has each channel follow the output of the regulator to minimize dissipation. The easier would be 4 independent 100W smps with a linear regulator attached to each output. I designed something like this 1-2 year ago, it was a synchronous forward converter that ran 12V@10A max and depending on the wiring, each board could work independently or be controlled by the first board's control loop (full analog, no mcu) maxing out at 8 boards cascaded up to 80A. with 500mV output ripple.
This would be a difficult project but pretty rewarding. I can help with almost everything down to designing the transformers/inductors etc.

[Anonymous No.2711830]

>>2709490
I have an analog stereo audio output from a device (it has 4 mono audio lines for inputs). Can I just solder those lines to an MONO audio plug without any issues? Provided I figure out which is ground, L and R on the output device. Shitty pic related.

[Anonymous No.2711854]

>>2711726
I love the logic inverter idea at the 5V PWM stage and will experiment with it, but can you expand on how to use the outputs of the H bridges without causing some kind of ground loop? After all they are using two outputs and I need to feed just one input relative to ground?

[Anonymous No.2711857]

>>2711830
I found this for you searching for "combine stereo to mono circuit": https://techtalk.parts-express.com/forum/tech-talk-forum/60443-stereo-to-mono-summing-circuit

The schematic showing the use of an Op Amp looks promising? Directly connecting your amp could blow the amp if the two channels are in opposition during certain conditions of phasing in your original drawing.

[Anonymous No.2711886]

>>2711753
my ideal setup would basically be what you described. discrete "cc/cv linear regulator" being fed by an upstream offline SMPS that tracks the linear regulator's commanded voltage plus a couple volts (to account for dropout and simultaneously minimize wasted dissipation power.) i'd like a digital interface so i'll use the usual "inject current with an MCU controlling a DAC" trick to accomplish this.

do you have any recommendations on offline topologies, forward converter vs push pull? the other anon brought up a good point with flyback converters and the air gap bullshit which i would like to avoid. i want the ability to adjust down to 0V on the linear regulator output, or ~2V on the SMPS output. not sure if one topology is better suited for wide output range variations?

[Anonymous No.2711917]

>>2711745
But the resistor is parallel to the input of the receiver so why would the signal care?

[Anonymous No.2711918]

>>2711917
What is the impedance of receiver input?

[Anonymous No.2711932]

>>2711830
Inputs are fine to short together, as they tend to be high impedance. Outputs are not fine, cuz you risk damaging them, but I think adding 100 or 1k resistors in series with each line should be okay.
Phase issues are also a concern

[Anonymous No.2711943]

>>2711918
about tree fitty

[Anonymous No.2711944]

>>2711335
b/c someone on /g/ gave him shit about it like >>2711344 said.

[Anonymous No.2711970]

>>2711918
It doesn't matter Aslong as it's different from the transmission line impedance

[Anonymous No.2711976]

>>2711649
I can wholeheartedly recommended solder wick

[Anonymous No.2711983]

>>2711944
>/g/ gave him shit

having just gone thru the trauma of turning off daylight-savings on a dozen old gadgets, i concur.
everything with a clock needs to be connected to the internet or a radio station like WWV.

[Anonymous No.2711999]

Did the DS1054Z become too popular and overpriced?
I can get the new 12-bit DHO814 for less and it seems better in every way.

[Anonymous No.2712005]

>>2711983
>doesn't just subtract an hour in his head
all my clocks have been wrong for years

[Anonymous No.2712016]

>>2711886
>do you have any recommendations on offline topologies, forward converter vs push pull?
I'd choose forward, because it's not overkill for the 4x100W like a push-pull and can pull off the 400W output as well. The control loop is easier as well. I might be biased tho, because I'm more comfortable with forward.
>the other anon brought up a good point with flyback converters and the air gap bullshit which i would like to avoid
You won't need an air gap for the transformer, but depending the core material for the output choke you might have to. I used N27 EC42 core in mine (that was available for me) and I needed a considerable airgap.
>i want the ability to adjust down to 0V on the linear regulator output
That's npt a problem
>or ~2V on the SMPS output
Now that would be problematic. A 22V-33V could be doable. I'll look into it, but can't really think of anything to widen the range. The problem with this is that the linear regulator has to carry the whole thing and drawing 3A at 3V with 22V input is gonna turn the whole thing into an oven. Maybe have a 2-3 channel forward converter that could cover the whole range, but this is becoming pretty complex with a lot of inductive parts now. You could also drop the voltage through 2-3 regulator phases to distribute the power dissipation. The size could still be more managable tho than a tapped transformer->voltage regulator, but it's infinitly more complex. But you would need a big ass heatsink (preferably attached to the metal housing of the build) and probably a fan too
>not sure if one topology is better suited for wide output range variations?
Unfortunatley it's either the voltage or the current you base your control circuit around, so both of them can't be variable to a degree like this

Now that I somewhat thought this through, albeit it would be a really cool project, I'd choose the big ass transformer&regulator approach. It's just far easier and cheaper (all the FETs/IGBTs would probably cost 100-150$ alone

[Anonymous No.2712017]

>>2712016
>I'll look into it, but can't really think of anything to widen the range.
shouldn't it be possible with some sort of a switching topology? i mean my chink switching bench supply manages to do it and i can't imagine it uses some exotic topology to accomplish this.

[Anonymous No.2712035]

>>2712017
I got you, so they do something like an isolated smps -> non isolated smps -> regulator. The isolated smps is fixed voltage, and the non isolated smps (simple buck) and regulator is controlled.
So i'd go with forward converter->buck converter->linear regulator

[Anonymous No.2712045]

>>2711999
>buying a new scope instead of a CRT relic
ngmi

>>2712016
Why can’t you get wide output variations, is it because it’s an off-line converter where you’re ultimately powering the converter off itself? Buck and boost converters can easily get a ratio of 2-3 while retaining efficiency, and that buck can get all the way to 0V with the right circuitry. If the off-line topology is the issue, then you’re far better off using a cheap hand AC-to-DC converter as your baseline (e.g. 2nd hand ATX) and converting with a switching DC-to-DC stage from there. If the rails don’t need to be isolated from one another the magnetics are far easier. If they do need to be isolated you could faff about with transformers and optocouplers, or you could just use seperate AC-to-DC supplies for each rail.

[Anonymous No.2712051]

>>2712045
I'm with you. I got a couple slightly more modern (though none with onscreen frequency or digital voltage displays) than this but my daily driver? Pic rel. It seems pretty resilient if I make a booboo poking something I shouldn't oughta, it's a trooper.

[Anonymous No.2712134]

>>2711713
Sounds great
>>2711976
Any certain material grade it should be?

[Anonymous No.2712170]

I just bought a lifetime supply of opamps and it feels liberating

[Anonymous No.2712233]

rollolol

[Anonymous No.2712253]

What are important parameters I should look at when using bidirectional TVS diodes for ESD protection?

[Anonymous No.2712264]

I have 2 houses distant of about 200m of lines and on the same electrical cable. For curiosity purpose, I'd like to use power line communication to exchange signals between them, over the public grid. Do you think it's easily doable ?
Do you think

[Anonymous No.2712266]

I have 2 houses distant of about 200m of lines and on the same electrical cable. For curiosity purpose, I'd like to use power line communication to exchange signals between them, over the public grid. Do you think it's easily doable ?
Concerning laws and the use of frequency bands, I requested my FCC local-equivalent. They replied me they have the competence to supervise its use.. which means somehow it's FFA.

[Anonymous No.2712270]

>>2712266
>they have the competence
they do not have the competence, sorry.

[Anonymous No.2712275]

>>2712266
If both houses are wired to a single panel powered from one external line transformer then it will work. If the houses have separate panels and transformers, it won't work.

[Anonymous No.2712298]

>>2709490
Will i be ready for soddering, b-bros?

[Anonymous No.2712301]

>>2712298
everything looks good except for those helping hands. ive owned a pair before, they suck ass. ones like pic related are 1000x better, although mine doesnt have the weird clamp attachment.

[Anonymous No.2712302]

>>2712301
>>2712298
would help if i attached the pic

[Anonymous No.2712303]

>>2712302
That looks like it hurts.

[Anonymous No.2712304]

Looking for a programmable, fastled compatible (or similar) ropelight like the one in the picture, i want them to be light all around.

Any idea what these are commercially available as?
Ropelight on ali just shows me 2812b and led strips with a flex PCB underside that don't illuminate

[Anonymous No.2712312]

>>2712304
programmable might be a problem. ditch that and you are ok.
https://www.ultraleds.co.uk/tagrar-circular-360-led-neon-flex-18mm-24v-warm-white-2900k.html

[Anonymous No.2712325]

>>2711649
You probably don't need desoldering gun, but pic related is the best solder sucker I've found and works great for through-hole work I've been doing.
>>2712301
I have that same helping hands, got it free, and always wondered what the center thing was for (it was missing the glass, just an empty stump.) Agree it's a POS and now thinking I need to get >>2712302
>>2712303
It would be painful

[Anonymous No.2712332]

>>2712325
>It would be painful
For you.

[Anonymous No.2712334]

>>2712301
>>2712302
Where do i get this from?
Also how about pic related?

[Anonymous No.2712337]

>>2712334
>Where do i get this from?

go to the Amazon whore house and ask for the room where they keep the "soldering helping hands" and you'll see more fine examples than your mind can handle.

[Anonymous No.2712338]

>>2712334
https://www.youtube.com/watch?v=C4ACT2w93Mc
https://www.youtube.com/watch?v=iZygyqx6AOY

[Anonymous No.2712354]

>>2712312
Good enough price, I also like it's dimmable.
For the price I guess I can't ask much more, thanks for the recommendation, gonna find a provider that sells to Spain

[Anonymous No.2712362]

>>2712134
>Any certain material grade it should be?
not sure what you mean by that but it should be braided copper and don't go for much wider than your solder tip (as a rule of thumb I just pulled out of my ass) if you have modest power or you'll risk getting it stuck on your workpiece.

[Anonymous No.2712397]

>>2712334
If you 3D print, there are a ton of them on there. I was going to design one but now don't think I'll bother.
Search for "third hand" which is the other name these go by.

[Anonymous No.2712399]

>>2712397
> on Thingiverse, etc.

[Anonymous No.2712403]

>>2712399
he said thingy
huhuhuh

[Anonymous No.2712452]

how do i into creating synthesizers / audio effects?
are there some resources online or books i can buy?
i know nohing about electonics but the books in the op cover that i guess

[Anonymous No.2712469]

>>2712452
You can start here
https://www.youtube.com/@MoritzKlein0

Otherwise get ready for fun adventures in math. You can start with algebra, complex numbers, then move to calculus, differential equations, linear time invariant systems, fourier and laplace transforms, convolution, then additionally discrete versions of those so you can do DSP, z-transform, bilinear transform, various forms of FIR, IIR filters... If you want to focus more on analog side then add in circuit analysis, transistors and transistor modelling, transfer functions, bode plots... You really need to know your fundamentals very well. Start by reverse engineering old audio gear and try to understand how it works.

[Anonymous No.2712592]

>>2712298
Correct T12 pencil selection. But the built-in PSU ones can be kinda sketchy QC-wise, try and go for the ones without a PSU inside them along with a name-brand 24V PSU. Might be able to get such a PSU from a thrift store even.

PCB clamping vices are better than those helping hands. Or just >>2712338.

>>2712325
You're better off going for a heated desoldering iron than one of these.

[Anonymous No.2712673]

Can anyone tell me what the right way of doing this would be? I wanted to control this fan with a raspberry pi pico. The coils are the capacitive switches which turn the fan on and control the speed and so on.

So I tied a bit of wire around one, put the other end of it into a gpio pin on a raspberry pi pico and sent a pin_out signal for half a second... (3.3v signal) Fried both the fan and the pico. Luckily not my pc. Any pointers on why this happened and what I should have done so I can learn from this?

[Anonymous No.2712681]

>>2712673
First of all, that's going to be a mains-referenced circuit. So any interfacing you do with it must either be electrically isolated from the world outside the fan (e.g. pi pico trapped inside fan with own ac-to-dc psu and only communicates wirelessly), or done via optocouplers/transformers/relays. Or both. Using this kind of isolation between a low voltage circuit and a high voltage circuit is generally a good idea anyhow, even when isolation isn't necessary.

You have two main options for automating this fan. Either use the microcontroller to "press" the buttons, or replace the existing controller with a microcontroller that directly controls the TRIACs for the motor windings.

The former method will still need to be somewhat complex since I think you'll want feedback (e.g. to know what speed the fan is set to), but it should be reasonably easy still. I'd reverse engineer the capacitive touch circuit. I'm betting you can use optoTRIACs or relays with resistors or capacitors in series to create mock touch-pad presses. For the feedback, using optocouplers off the TRIAC or display outputs would probably be doable, or you could use a current transformer clipped over one of the input wires.

This latter method is definitely doable just by using optoTRIACs to toggle those TRIACs, but if you want to use the same display and keep the buttons usable it will end up being more complicated. If the controller on that fan is dead this method is your only option, maybe the 7-seg display is still alive. Double check any fuses or circuit breakers that may have been in series.

[Anonymous No.2712715]

>>2712673
First off, I'd use arduino nanos, which are ~$10 for a pack of 5. It matters what they cost if you're learning and burning them up in the process. At least it was a pico and not a pi.
Second, rather than trying to induce that circuit to work, I'd completely replace it and use something like pic related relay board to actuate those H/M/L/SW lines, which like >>2712681 says appear to be mains voltage.
I'm not sure what the buzzer or the little LCD display are telling you, but both could be run by the microcontroller. I'd replace the LCD with a smal OLED display, or just omit it.
> t. just did a very similar project adding a brain to a piece of equipment

[Anonymous No.2712716]

>>2712673
I would've probably just ripped out the existing controller and replaced it, either with triacs, or even simpler a mains-rated relay (with mosfet + flyback diode to not overload the pico)

[Anonymous No.2712717]

>>2712715
>arduino nanos
Eh, not like the pico costs much itself. The quality of life features more than make up for the price difference in my opinion.

[Anonymous No.2712720]

>>2712717
Admit I soured on Raspberry offerings after RPi got really hard to buy, and the nanos knockoffs are so cheap I buy packs of them.
I briefly read up on the pico; what's the QoL improvements? Speed and internal memory? Adv to nano is there's a gazillion example projects w/ code.

[Anonymous No.2712741]

>>2712720
Hugely more powerful. Dual core 133MHz, overclockable to over 400. 264KB of RAM, 2MB of flash.
Many more peripherals, and routable to more pins. The cherry on top is the PIO, which gives FPGAs a run for their money and can easily mimic other peripherals on any pin. Need another UART, USB port, VGA, hell even HDMI? PIO. It gets shit done.
There is an arduino port available if you don't want to use the bare C SDK, and alternatively there's micropython which sets up a filesystem and other convenience features for lower performance applications (which is many of them to be honest).

[Anonymous No.2712753]

>>2712741
People still buy teensy boards. lmao

[Anonymous No.2712769]

>>2712741
I guess what I'm getting hung up on is the use case. Microcontrollers (pico/nano) and SBCs (RPi,OrangePi, etc) both have different use cases.
Most of the stuff I use nano for is controlling devices, either in closed loop or using input from a computer. Programs are pretty simple / short and mostly need solid timing. Whereas the SBCs allow you to run a cheap/quick OS to do more complex programming, provide a gui, network, file handling, etc. The pico seems like it lands somewhere inbetween. Maybe that's the point, but I can't figure out what I'd use it for.
I looked online, and most/all of the example projects for pico could be done w/ a nano... and I suspect the example projects aren't really using the full capabilities of the pico.
Give me an example that would use the pico... too complex for nano and SBC would be overkill.

[Anonymous No.2712776]

>>2712741
>>2712769
Looking at your post again. I think the use case is quick digital transformation stuff... video and audio, plus having memory to access models to do that work. I've actually got a project now that's too complex for nano but might be right speed for pico: onboard facial recognition and tracking, along w/ wifi. I'll have to study it more.

[Anonymous No.2712788]

>>2712769
>Give me an example that would use the pico... too complex for nano and SBC would be overkill.
Anything that needs fast/complex IO or signal processing. I've seen it used for arbitrary waveform generators, signal analyzers (both at full clock speed), console mods, driving very big LED panels, other image processing, etc.
It also covers the use case of using scripts on an SBC to glue stuff together, because micropython acts like a pseudo-OS making it behave like an SBC (at the cost of performance headroom, though it can still perform better than low end microcontrollers).
I treat it as more of a swiss army knife. It has enough performance headroom and peripherals that it can do basically whatever I want, all the way up to low-end SBC stuff, while having a price more in line with other microcontrollers.
As an alternative to a nano, I guess it comes down to what you value more - the extra $1 to $2, or basically never running into hardware limitations.

[Anonymous No.2712795]

>>2712769
you don't need an rPi. ignore the windbag shill, he's trying to hook you into feature creep.

[Anonymous No.2712804]

>>2712795
>ignore the windbag shill,

If I were a mod I'd drag this whole mini-thread over to /mcg/ where they love to argue about bullshit, and leave /ohm/ to the grownups.

(so, why does pico w cost twice what esp32 costs, when they are very similar)

[Anonymous No.2712924]

>>2712741
Yeah but literally none of that matters for this project. And if you want to control it wirelessly, an ESP would be cheaper.
Of course the chad move is to make your own PCB and solder an MCU IC directly onto it instead of using a dev-board.

Just use an ATtiny13.

[Anonymous No.2712928]

>>2712924
>ATtiny13
Consider CH32V003.

[Anonymous No.2712998]

>>2712681
>>2712715
>>2712716

Thanks for the responses, I have a bunch of isolated relays laying around so Ill go with that method. Do I not need to worry about the mains voltage being too high for what the motor needs?

Also my reason for using the Pico simply they are made in the UK and I'm british so I want to support that. The slight markup is worth it for me over an ESP32

[Anonymous No.2713031]

>>2712998
>Do I not need to worry about the mains voltage being too high for what the motor needs?
Presumably the mains voltage was being switched directly to the windings of the fan. I’d guess they’re switched in a binary arrangement for steadily increasing the power level (0000, 0001, 0010, 0011, etc.), but one may be a start-only winding that should only be activated temporarily.

I’d reverse engineer the thing to see what’s what. With the relays you’d probably just replace the TRIAC switches and PCB entirely, just check the relays’ voltage and current ratings. You can re-implement capacitive touch buttons and a display if you want.
>I'm british so I want to support that
Also lower chance of spyware!

[Anonymous No.2713037]

>>2712673
The transistors control which motor windings get power (High,Medium,Low) and toggle the power switch (SW). As others have said, you need isolation between the fan control board and whatever uC you use to control it.

[Anonymous No.2713141]

I've been watching this video...
https://www.youtube.com/watch?v=AiY7riVjaB8

And I realized something, if I want to make an electrically actuated non-RoHS portable particle accelerator, I should give particle a spin before accelerating using a capacitor bank and a triac. This would increase accuracy.
And whole spin thing made me think, are conventional combustion type particle accelerator even efficient? How much energy is wasted on making dents in the particle to make it spin?

[Anonymous No.2713150]

>>2713141
girlfriend what the bloody fuck are you talking about

[Anonymous No.2713151]

>>2713150
>capacitor
>triac
>coil
>pellet/particle
idk, its obvious what is it.

[Anonymous No.2713194]

>>2713141
The particle accelerator walls do heat up as a result of their interactions with the particle, which is likely more significant the more spin you give that particle. But the source of energy for combustion devices is pretty dense so it doesn't really matter how much energy you lose, I doubt it's more than 20% loss.

If you have the ability to do so, you could add fluid-dynamic aids to the stability of the particle, as found on the particles used by large-diameter vehicle-mounted no-spin combustion particle accelerators. Probably a lot easier than having spin-deflection coils and some sort of permanent-magnet/reluctance/induction structure inside the particle.

You can also use combustion-driven electrical pulse generators to drive a magnetic particle accelerator, which kinda defeats the purpose but I bet you could accelerate particles far faster that pure combustion, and maybe with more space-efficiency than pure electric.

incredible terraformars roach face on that idat thumbnail there.

[Anonymous No.2713244]

>>2712998
>Do I not need to worry about the mains voltage being too high for what the motor needs?
Ah... yes?
Ideally you'd measure the output of the H/M/L/SW lines, and match that voltage. Less ideally you could look for a rating on the fan motor itself. Do you know, or do you know how to tell?

[Anonymous No.2713258]

>>2713244
>Ah... yes?

what a silly thing to say.
why would they sell a 120V fan that cant handle 120V?
the typical 3-speed control for standing fans involves switching power to diff coils, or using diff value caps in series.

[Anonymous No.2713274]

>>2712325
i bought a chink clone of that solder sucker and it's awful. the nozzle diameter is way too small and tends to plug up completely. this chinky ax-108 is much better imo.

[Anonymous No.2713380]

>>2713274
lol is it actually that large?
The real thing is Japan made and works great. Some types of tools really aren't worth skimping on; the cheap versions are nonfunctional and worthless.

[Anonymous No.2713389]

are these things reliable? i'm trying to test the secondary on an SMPS. i know (from the schematic) that it's center tapped on the secondary side. they don't tell me the values but,

my meme test instrument is telling me:
top to bottom: 0.08 mH
(top or bottom) to center tap: 0.14 mH

i am expecting:
top to bottom: x
(top or bottom) to center tap: (1/4)*x

[Anonymous No.2713434]

>>2713389
they suck for small inductors, you usually want at least 1 mH

[Anonymous No.2713443]

Would someone please help me with a wiring diagram to hook up a small led light on a wire to this telegram key? I have 0 experience but I can follow instructions and would appreciate it. Here is the top

[Anonymous No.2713444]

>>2713443
And here’s the bottom view

[Anonymous No.2713457]

>>2713443

google "led polarity" to learn how to orient the led. other than that, figure out how your key works and which pair of terminals you want to make or break this simple circuit in any of the wires.

[Anonymous No.2713459]

>>2713457
and in case that's not enough: https://www.circuits-diy.com/simple-basic-led-circuit-beginner-electronics-project/

[Anonymous No.2713518]

>>2713274
What you have there is a cheap chinese clone of the famous “SOLDAPULLT” solder sucker by Edsyn.

Take that fucking thing, toss it in the trash, and get a real one.

A lot of chinese crap just looks enough like the thing they replicated, but isn’t even the actual thing it’s supposed to be. Yeah, it’s that bad.

[Anonymous No.2713520]

>>2713389
You can calculate the rough accuracy of these by looking at the schematic to figure out the LC time constant, and knowing the timing capabilities of the MCU for a given crystal frequency. There’s probably already someone who’s done this already.

[Anonymous No.2713548]

Working with headphone cables is so fucking ass. Everything is so small.

[Anonymous No.2713555]

>>2713548
Use optical magnification to aid you in your quest.

[Anonymous No.2713568]

>>2713548
why bother with that shit? just add these to your cans and buy 100' of speaker wire for $10

[Anonymous No.2713574]

>>2713568
Why don't headphones use magnetic connectors?

[Anonymous No.2713579]

i have a burnt up 1KW transformer (40V, 20A) for an SMPS that i want to replicate with new parts. ive never wound my own transformers before but im studying the construction and it doesnt look TOO challenging. is it really as simple as following the winding pattern or is there some sort of hidden magic that im overlooking? the biggest question so far is what the core material is but the physical dimensions seem to line up with TDK 49/25/16. i take it varnishing is necessary as well?

[Anonymous No.2713583]

>>2713555
Also the fact that there's that weird insulation layer where you can break the cable when frying it off.

>>2713568
What's the thickest wire gage you can use for headphones?

[Anonymous No.2713594]

> Scherz & Monk, Practical Electronics for Inventors
> arguably has minor issues with mains grounding
qrd? Been slowly using the book to fill any gaps in my understanding

[Anonymous No.2713637]

Can i do anything neat with these capacitors? I have them from treadmill power supplies and cant think of anything to use them for.

[Anonymous No.2713644]

>>2713579
Matching the primary and secondary inductance with the old transformer is the main thing. If you don't know those values (e.g. from the old transformer's datasheet) then you'll have to infer them from the number of windings and the type of core. Is it a flyback topology? If so you need to care an air-gap, which I believe deliberately lowers the coupling coefficient to add leakage inductance for energy storage between cycles.

>>2713594
I think it was just something about the connection of neutral and protective-earth behind the breaker panel, can't remember what people were sperging out about but it wasn't exactly radical.

>>2713637
Input caps for a rectified mains circuit. A diy single-phase VFD sounds fun if you've got some induction-motor powered machinery/tooling, same for a general-purpose high-voltage amplifier (probably class-D but maybe vacuum tube). Or put them towards something like a coil-gun or insect zapping circuit or whatever.

[Anonymous No.2713694]

What are some good projects to understand how 555 timers and flip flops work in practical applications?

[Anonymous No.2713703]

>>2713694
Picrel is an award winning circuit using the 555.
It might just be the most advanced use of the 555 ever devised.
Figure out how and why it works, and you’ll be an expert.

[Anonymous No.2713708]

>>2713574
> why don’t they use these ultra expensive, gold plated, patented connectors?
Cost.

>>2713579
> varnish?
Only if it’s noisy. Some can vibrate at whatever frequency (i.e. 60 Hz for mains)

>>2713637
> do with capacitors
That’s a pulsating DC smoothing capacitor.
You might have some old transformer based wall warts or power supplies you can just add it to. Especially if they’re old, capacitors have a lifespan.
What brand is it? If it’s not Panasonic or Nichicon then take it, throw it on the floor, and stomp on it while simultaneously twisting and smearing and place remnants in the round file.

[Anonymous No.2713716]

>>2713703
Can someone explain to me why this style of solar charge controllers have dummy loads instead of just PWMing the battery? The cheap chinese PWM charge controllers I've seen don't have dummy resistors at all.

[Anonymous No.2713728]

>>2713716
> why dummy load?
It needs load to slow the dynamo. Similar problem with solar, but I don’t understand that one. Apparently it’s bad to run an unloaded solar cell in full sun.

[Anonymous No.2713748]

>>2713594
>qrd?

the book is correct about grounding.
some dumb kid asked his prof about it, and the ignorant prof got it wrong coz electrical code is not same as electronics.

>>2713637
>anything neat with these capacitors?

charge it up to 250V.
apply to someone's neck.
now unconscious, you can get their moneys and/or lose your virginity.
what could be neater?

[Anonymous No.2713754]

>>2713748
>charge it up to 250V.
>apply to someone's neck.
Just tested this. Woke up with a sore bum and $1 under my pillow. Neat.

[Anonymous No.2713755]

>>2713708
>Cost.
They aren't that expensive. Worth it for not having to futz around with soldering enameled wire.

[Anonymous No.2713757]

have you tried to reapply polarizing film to a monitor that has had its film delaminating due to age? there are some youtube videos about this but im just wondering if anyone here has tried it.

[Anonymous No.2713760]

>>2713757
Put the polarizing film on some eyeglass lenses.

[Anonymous No.2713766]

>>2713703
I'm an electronics noob. What do arrows pointing to resistors mean? I've seen them a few times. Last time I did electronics was 15 years ago and that was basic stuff only. Have never seen that kind of symbol before.

[Anonymous No.2713767]

>>2713748
Does that really work?
Asking for... science.

[Anonymous No.2713771]

>>2713766
>arrows pointing to resistors
Those are LEDs emitting light, and the arrows differentiate it from a regular diode.

[Anonymous No.2713773]

>>2713771
Not the leds, the arrows from pin 6 and 2 on the 555 pointing toward R2 and R1 respectively.

[Anonymous No.2713775]

>>2713773
Those are potentiometers - variable resistors.

[Anonymous No.2713778]

>>2713775
Oh, cool. I know what a pot is, but I never actually saw the symbol for it before.

[Anonymous No.2713780]

>>2713708
Its some chink brand. I found them in a dumpster by my work, im pretty sure its from a cheapo treadmill thats sold on amazon. They came on an aluminum
bracket but i melted that like a crackhead.
>>2713644
I might already be a VFD of sorts, it has hp labels as if for a motor. I wanted to power a vaccum motor for an exhaust setup but would the motor being AC be and issue? A coil gun or zapper sounds fun.

[Anonymous No.2713808]

>>2713778
>I know what a pot is, but I never actually saw the symbol for it before.
It can get confusing at times.

[Anonymous No.2713840]

>>2709490
assume i have a 1) floating mains powered device under test (via isolation transformer) and a 2) mains powered oscilloscope.

i know that scope ground terminals are common to one another, and are then connected to mains ground.

since the DUT is FLOATING, can i safely probe a high side FET gate in a half bridge driver (ground clip to "VS", probe clip to "HO") provided that i do not connect a ground clip to anything else (which should cause a short circuit and blow shit up)?

[Anonymous No.2713845]

>>2713840
Yes, if it's floating then you can connect ground to whatever you like and as long as both probe ground are on same node no smoke will appear. Scope and probe absolute voltage limits still apply though.

[Anonymous No.2713849]

>>2713457
>>2713459
Thank you! I made a signal light with it

[Anonymous No.2713921]

>>2713849
>I made a signal light with it
When you put it on your resume, write it as "half-duplex digital optical network".

[Anonymous No.2713937]

>>2713921
with OOK modulation of InGaN semiconductor-based electoruminescent emitter of photons by recombination of quantum charge carriers (Anon, et. al., 2023, IEEE Transactions on Communications)

[Anonymous No.2713947]

>>2713937
lmao
Susan from HR would just say you're overqualified.

[Anonymous No.2713989]

any EEs in here have an opinion on this design? https://github.com/jankae/LCR/tree/master i found this by chance and it looks great.

>cheap as hell
>off the shelf reports, nbd if i accidentally blow it up with a charged cap
>simple pcb, should be cheap to have jlcpcb make

the designer claims up to 200khz and impedance measurements down to 20 milliohms which is great for my uses.

[Anonymous No.2713991]

>>2713989

[Anonymous No.2714024]

>>2713989
just use a fast edge generator
https://www.youtube.com/watch?v=74fz9iwZ_sM

[Anonymous No.2714039]

Is there such thing as an LET (Light Emitting Transistor)?

[Anonymous No.2714045]

>>2714039
There are optocouplers/optoisolators.

[Anonymous No.2714050]

>>2709490
Hello friends. I am new to arduino and I have a project in mind that I can’t seem to make work. So I have one of these 128 by 64 Oled displays and I was able to pretty easily make bitmaps of the images I wanted to use but what I need is control. How do I add a potentiometer and a push button to this in order to make a kind of selection menu? I understand how to look up these tutorials and get each of these components working individually but when it comes to incorporating them all in the loop function it gets a little nebulous. What I want to do is get the position of the pot and use that to inform which image to display and then use the push button to perform an action relative to that position and the image that’s displayed

[Anonymous No.2714065]

>>2714050
youre basically trying to make your own graphics library. start simple. do the pot thing first with the button, get it to do something simple based on the pots position - like change the color of a rgb led. from there it should be simple, instead of changing the color of an led, replace that with the functionality to update the screen, hell even just update a single row of pixels to make it simple. also this really is a /mcg/ topic

[Anonymous No.2714068]

>>2714065
Good advice and thank you for letting me know about the other thread

[Anonymous No.2714090]

ive watched a few teardown videos on programmable AC power supplies. it appears to be rectified mains being fed into a full bridge transformer, being switched with sinusoidal PWM or DDS for the fancier waveforms. im confused about the transformer stage. pic related does 15 hz to 2 khz output but the teardowns on similar units show a ferrite transformer. i thought high frequency transformers typically performed like shit when switched this slow?

[Anonymous No.2714128]

>>2714050
Learn how to actually code instead of just copy-pasting lines from examples. Hard-mode: use no libraries or Arduino functions.

>>2714090
If they’re switching the PWM directly into the transformer then the transformer will be operating at the switching speed, the low-pass filtration will be after the transformer. This is the same as what modern pure-sine inverters do. Traditional-style UPSs on the other hand need a big iron transformer because they filter the power before it goes through the transformer.

I don’t think ferrite is actually bad at mains transformers (see audio toroidal transformers) but mains frequency transformers must necessarily be a lot bulkier. Rather, laminated silicon steel cores are worse at higher frequencies, but are cheaper than ferrite cores. So it could be either. There’s a whole lot of different ferrite materials anyhow.

[Anonymous No.2714167]

>>2714128
i'm not an EE so i never studied filter theory much (or really at all beyond understanding qualitatively what happens).... but how do they get a clean 15 hz to 2000 hz output with a fixed output filter?

[Anonymous No.2714170]

>>2714167
Theres low pass and high pass filters. I think its just different capacitance values. Low freq prolly needs large caps which would be electolytic and have high ESR resistance.

[Anonymous No.2714204]

>>2711411
>pro-tip from the guy: when buying HDD, buy robust ones made for the industry. don't buy faggy shit like ones made for creators, gamers, or home-use.
That's just general advice, everything for the consumer market is just garbage, boots, clothes, laptops.
It's much better to buy something that's milsurp, business, professional or enterprise, that's second hand and "last gen". It will last you for 10 years easily rather than the new and shiny polished turd that will fall apart after few months to a year of usage

[Anonymous No.2714207]

>>2714204
That's purely because of how shit everything (including enterprise shit) is today. The reason last gen shit works better is that it's last gen, not that it's last gen enterprise.
I have been using the same hdd for the past 15 years. A consumer seagate.
Meanwhile all the enterprise WD drives at work die within a few months despite being used less than I use my HDD at home.

[Anonymous No.2714208]

>>2714207
>That's purely because of how shit everything (including enterprise shit) is today. The reason last gen shit works better is that it's last gen, not that it's last gen enterprise.
Probably, haven't got a chance to use new enterprise stuff, even at work all machines we use are old, "if it ain't broke don't fix it".
From what I've seen new "enterprise" laptops have power connectors soldered to the motherboard instead of being mounted in the chasis with a cable and connector to the board.
That's just asking for trouble.
Shame that it seems in the future everything including enterprise/business/industrial gear will be shit, and not talking about laptops

[Anonymous No.2714218]

>>2714045
Yeah but I mean the BE junction itself

[Anonymous No.2714222]

I'm an EE undergrad graduating in 4 weeks. I just got my first job offer for an EE position. I'm not sure what to think of it.
They're offering a salary of $64k a year starting. This feels like a huge lowball, especially with my experience.
To sweeten the deal, it offers health, dental, and vision insurance and a 401K match of 6%. I don't know how good any of this is.

Given my inexperience, I don't know what to expect or if I had set my expectations too high. What do you guys have to say about it?

[Anonymous No.2714226]

>>2713989
>>2713991
4-wire testers are cool.
>eagle files
>no pdf schematic
Post a schematic image if you want more opinions of it.

>>2714024
You have to measure at multiple frequencies to get a read of both inductance and ESR, plus that's not 4-wire sensing so you can't reasonably measure ESRs below ~1Ω.

>>2714167
>how do they get a clean 15 hz to 2000 hz output with a fixed output filter
They switch the FETs at a (probably fixed) frequency between 20kHz and 1MHz. They have an LC low-pass filter with a corner frequency of ~2kHz, maybe a tad higher. The PWM's fundamental frequency has at least 40dB of attenuation, while the resultant desired mains frequency has no more than 3dB of attenuation.

It's basically a non-resonant class-D amplifier, probably.

>>2714218
The BE junction of a (3 pin) phototransistor might emit light if you pass current through it (watch it with a cellphone camera that lacks an IR filter), but what would that give you compared to an IR LED?

>>2714222
Does it sound like fun work? Does it have opportunity to climb to a higher paying position? Would it look particularly good on your CV?

[Anonymous No.2714235]

>>2714222
> undergrad
> my experience

I’d jump all over that. There’s lots of people who are having trouble finding work. You can always quit later.
No idea wtf is wong with zoomers nowadays.
High school drop outs want 6 figure salaries and company cars, LOL.

[Anonymous No.2714238]

>>2714226
It does sound like fun work and it's in a field I really like (which I made clear in the interview and is probably why they think they can bust my balls)

the thing is it's in a high CoL area (Orlando) so that also plays a part

>>2714235
I wouldn't say "my experience" if I didn't mean it. I'm the RF lead for a school club. I can't say too much without doxing myself but we made a functional working prototype of our own design for an RF plasma physics tool, for several orders of magnitude less than other graduate level research programs have done around the country.
I also have multiple advanced signal processing projects under my belt, including an arbitrary waveform function generator, a digitally-controlled analog vocoder, multiple digitally-controlled analog synthesizers, and various hardware DSP based synths and audio effect suites

[Anonymous No.2714253]

>>2714238
> experience demonstrating projects.
I’m not trying to be an ass but if I read that stuff, I’m thinking you hooked up magnetron from an old microwave and you’re in a technopunk band in your spare time. Is any of that stuff even remotely what this company does?
I’m going to go listen to Bony M’s “nightflight to venus” with that cool vocoded Cylon voice. You should too. Don’t watch the video, it’s disturbing. Luckily these new “music video” things weren't really a thing then, and probably won’t go anywhere.

[Anonymous No.2714257]

>>2714253
My bad, I thought you were being facetious. That's the exact kind of "experience" I would expect from undergrads too, that's why I was hoping my actual experience would set me apart and get me a higher starting salary.
I got the jams queued up.

[Anonymous No.2714300]

Holy shit the CD4007 is versatile. But does anyone have a pdf datasheet that is:
>more than 4 pages long (i.e. actually has electrical characteristics)
>made of searchable text instead of jpegs
>shows the FET body connection
>doesn't make a mistake in its schematics
pic related is from two sections of the Intersil datasheet, the pins 2 and 11 are incorrectly shown connecting to pin 14.

appnote recommendations welcome too

[Anonymous No.2714317]

>>2714300

I don't know what a fet body connection is, and this will probably disappoint you too: "Note: All P-channel substrates are connected to VDD and all N-channel substrates are connected to VSS", but otherwise it might be of some use:

https://www.futurlec.com/4000Series/CD4007.shtml

[Anonymous No.2714328]

>>2714226
>Post a schematic image if you want more opinions of it.

see pic. there's other pages in the schematic but it's just voltage regulators and the MCU.

[Anonymous No.2714349]

>>2714238
>a high CoL area (Orlando)
LOL. HAHAHAHAHHAhahahaha.
No. Orlando is not high CoL. Try NYC or SF sometime, places I've spent an entire career avoiding.
The real issue is it's FL, which is a professional backwater. If you want more money, go other places where EE stuff is designed and made. And no, sorry, I don't know where EEs go these days. In the PNW, it was places like HP.
My advice: take the job, any job that pays, then get a new one in a couple years.
> t. been stuck in S FL for over 10 years and now don't want to leave

[Anonymous No.2714359]

>>2714226
>They switch the FETs at a (probably fixed) frequency between 20kHz and 1MHz. They have an LC low-pass filter with a corner frequency of ~2kHz, maybe a tad higher. The PWM's fundamental frequency has at least 40dB of attenuation, while the resultant desired mains frequency has no more than 3dB of attenuation.

it looks like programmable AC sources typically use a "transformerless inverter" topology. i get that you can vary the output voltage from 0-300V by modulating the duty cycle of the FETs. i get that you can vary the output frequency by modulating the switching frequency of the FETs. but im not understanding the relationship between switching frequency and the filtered output frequency which is 15 hz to 2 khz.

lets say 20 khz switching frequency and your lc filter does a cutoff on anything above 2 khz. get a nice filtered 2 khz output. does that proportionality stay in effect so e.g. if you wanted 15 hz output you would do (2 khz/15 hz) * 20 khz switching = 133 hz switching frequency?

[Anonymous No.2714363]

>>2714359
https://www.omnicalculator.com/physics/capacitive-reactance

[Anonymous No.2714458]

>>2714300
A lot of the cmos logic family including plain old inverters and nand gates look like that inside. When CMOS first came out there was an initial trend to use them as general purpose, high input impedance analog amplifiers.

Although general interest and knowledge about analog design was more common back then. Nowadays, people consider “python code” to be low level design.

[Anonymous No.2714481]

any good lipo4 black Friday sales?

[Anonymous No.2714586]

>>2714328
Looks neat, I'm assuming that RE0 is a DAC output that controls the current source, but not sure about DE0's connection to I-, if that's also a DAC pin can it handle the full output current?

>>2714359
See pic related. The only switching frequencies present are the PWM frequency and its harmonics, but the duty-cycle varies at a much slower speed. Low-pass filtering the PWM waveform results in the whole thing being smoothed out to look like a sine wave. Look at how class-D amplifiers work.

>>2714481
Do you mean LiFePO4 (lithium iron phosphate chemistry), or lipo (lithium polymer pouch)?

[Anonymous No.2714587]

>>2714586
> lipo
That would be lipopo

So he means LiFePO4popo

[Anonymous No.2714597]

>>2714586
Lithium iron!!

[Anonymous No.2714631]

>>2709490
Have old digital piano I turned into a midi controller with /diy/'s help a year or two back.
Getting random loud notes (usually means the first contact isn't registering so it sees an instantaneous keypress at the second contact).
Cleaning the contact strips was no longer cutting it, would be back to the same shit the same day or even an hour later.
Bought brand new unused contact strip, installed in piano (and dropped the keyboard and broke 11 keys but that's not the point).
Still getting loud notes.
Only other point of failure would be copper pads on the circuit boards. Do those go bad? Residual carbon on them from the old worn contact strips maybe?
Nothing else should be causing any issues because beyond that it's wired into a microcontroller I programmed.

Gonna bite the bullet and buy a new piano anyway due to breaking the keys but I still want to make this work or at least understand why it doesn't.

[Anonymous No.2714634]

>>2714631
Do you have a scope or a logic analyser? You assumption that it's missing one of the button presses is likely correct, but that may be anything from a worn carbon pad, to broken wiring, to a pullup resistor not working somehow, depending on where the measured signal stops. It could even even be a software bug in reading the value (e.g. in debouncing code) or failing to multiplex.

Consider going for a piano that uses hall effect, optical, or capacitive key switches. I can never trust those carbon contact strips to last.

[Anonymous No.2714641]

>>2714634
Sadly I only have a soldering iron and a crappy multimeter from harbor freight. I don't think it's the software since I wrote it myself, it's pretty simple and straightforward, and it had been working fine, and previously just cleaning the contact strip would fix it for a few months or so. I figure just something I had to do regularly since my house is both dusty and fairly humid.
Now that you mention it though, maybe it is a resistor or something else in the wiring of the key matrix. Just had some weird note issues earlier other than simply loud notes. I have some issues about keys not working since I've got it all wired up with jumpers into a breadboard and they get loose sometimes but that usually knocks out a single note across all the octaves, whereas this time I had a weird issue where if I held down A below middle C then the A above wouldn't sound, but it would otherwise. This didn't affect any other octaves though, only those two. Still could be a loose jumper but I've never had that issue before.
The loud notes are seemingly random though, there's no discernible pattern to them.

As far as different contacts, those are pretty rare as far as I know, almost all digital pianos use the shitty carbon dots or strips even now, except some high end shit with real piano actions and optical sensors and apparently some autistic German guy who puts optical sensors in Fatar action.
Wish I had room for a grand in my house, there is an old Yamaha Disklavier near me really cheap, and it has that full grand action with optical sensors. But alas, my house is too small.

[Anonymous No.2714671]

>>2714641
>I've got it all wired up with jumpers into a breadboard
Please wire it permanently, solderless breadboards are not for permanent projects

>As far as different contacts, those are pretty rare as far as I know
Wouldn't be too hard to modify an electric piano to use optical or hall setups, though tedious and maybe expensive. If the keys are multiplexed by rows and columns I don't believe it would be possible to use conventional hall-effect switches, but photodiodes/phototransistors would still work fine. Not that you couldn't use a bunch of one-of-N encoders or analog switch ICs instead. You could even just have one optical/magnetic sensor on each key and measure the analogue voltage to figure out how hard/quickly the key was pressed, instead of measuring delay. Being able to modulate a key after it's pressed isn't very piano-like, but would be very cool for a digital instrument.

[Anonymous No.2714706]

>>2714641
> I don't think it's the software since I wrote it myself
LOL, best quote ever.
Anyway, we found the problem.

[Anonymous No.2714770]

Is it possible to yarrr altium? I just want to fire it up and put a little bit of time into it to say i've used it but work is a mentor house?

[Anonymous No.2714845]

>>2714770
Don't make the same mistake as anon did who said during the interview that he pirated altium. Just use KiCad. Once you learn the concept any EDA software is similar anyways.

[Anonymous No.2714849]

>>2714845
he could have just said he used it with an educational license from an (online) course he took or some other bullshit
or sperged out about proprietary software being unethical

[Anonymous No.2714911]

>>2714845
lol why the fuck would i do that i'd just claim i used an eval/edu loicense. like i said i have xpedition through work i'd just like a glimpse of what it's like, since it is the most popular. just not sure i could get some kind of eval license. am i really not missing anything having never seen it. xpedition is a pretty steep learning curve i feel

[Anonymous No.2714924]

>>2714671
>Please wire it permanently, solderless breadboards are not for permanent projects
Been meaning to, just got lazy once things more or less worked. It's amazing how getting shit mostly done, or to a workable state really kills motivation to finish completely lol.

Wouldn't be too hard to modify an electric piano to use optical or hall setups, though tedious and maybe expensive. If the keys are multiplexed by rows and columns I don't believe it would be possible to use conventional hall-effect switches, but photodiodes/phototransistors would still work fine. Not that you couldn't use a bunch of one-of-N encoders or analog switch ICs instead. You could even just have one optical/magnetic sensor on each key and measure the analogue voltage to figure out how hard/quickly the key was pressed, instead of measuring delay. Being able to modulate a key after it's pressed isn't very piano-like, but would be very cool for a digital instrument.
That sort of thing is very tempting, but like you say probably extremely tedious and costly with all the parts. It has crossed my mind to get an old, free piano that's in decent shape (keyboard wise anyway) and try to rig up sensors on that.

>LOL, best quote ever.
Anyway, we found the problem.
While I get your point, my point was that it's a relatively simple bit of software, I know I'm reading the matrix correctly because I have a service manual and schematics, and other than that it's just a timer between two contacts to determine a velocity value, and sending off midi notes. And it worked fine for a couple of years, all the issues have been electrical, not software.

[Anonymous No.2714951]

>>2714631
>copper pads on the circuit boards. Do those go bad?

copper oxidizes creating an non-conductive layer.
an eraser will de-oxidize without causing damage.

[Anonymous No.2714994]

Solder quest continuation.
Where tf do I get high quality 60/40 when i'd not be able to get german stuff.

[Anonymous No.2714999]

>>2714994
Correction, elsod uses ROM1 which is rosin flux, mildly active. (RMA? )

[Anonymous No.2715001]

>>2714994
Who do you normally order from? Look for a big roll of Kester 44 on Digikey or Mouser so you can get free shipping.
>>2714999
>RMA
Yes, only buy RMA solder for general purpose, otherwise you need to thoroughly clean any flux residue to prevent corrosion.

[Anonymous No.2715006]

>>2715001
>Who do you normally order from?
Local small business scumbags, Chinese scumbags from aliexpress.
I can order from RS components. Mouser and digikey have high shipping cost for me.
> Kester 44
Maybe I can get it from amazon, as they do ship here.
>Yes, only buy RMA solder for general purpose, otherwise you need to thoroughly clean any flux residue to prevent corrosion.
I thought it was synthetic resin instead of rosin. It is just too clear to be normal rosin, but i guess they are using high grade one.

Other thing I kinda want to try is locally made 50/50 solder, but problem is that... it is 50/50, and idk if it is acid-core, or rosin core, doesn't say shit and manufacturer website is trash, and none of hardware stores near me stocks it. But given they claim it is for electrical stuff, it should be rosin-based.
50/50 is fine for soldering house wiring (idk who tf is perverted enough to do it, but it is possible and i've seen it) or car wiring, but for electronics it might be too shitty, probably comparable to real lead-free stuff, like SAC305 or idk 99SnNi+Ge+R solder or whatever

[Anonymous No.2715011]

>>2715006
>synthetic resin
That's fine too, but the board and components should be new / cleaned of oxides first for good results. As for the 50/50 mystery solder, I wouldn't take the chance unless you wanna use it for practice or desoldering. Even then it might eat your iron's tip.

[Anonymous No.2715017]

>>2715011
>As for the 50/50 mystery solder, I wouldn't take the chance unless you wanna use it for practice or desoldering. Even then it might eat your iron's tip.
I've used plumbing 50/50 solder in past, and it was fine-ish, but i ended up melting it with 95-5 making tin-lead-antimony alloy that was pretty good kek, maybe even stronger than 63/37. But that was coronavirus fun, and now thats impractical.
Also idk what flux it uses. Id give it a try if i see it sold near me.
As for tips, i use copper tips, because thats what i have and they are getting pitted fast anyway. Dont really care because they are dirt cheap.

[Anonymous No.2715021]

>>2714994
If you want the best shiniest solder joints then consider silver bearing solder

[Anonymous No.2715024]

>>2715021
I just want 60/40-ish solder for low price.
This one is good, but I think I can go even cheaper.

[Anonymous No.2715026]

I'm considering making a DIY 3D printed momentary switch for a project based on Hall Effect. Needs to be short throw (<0.1" / 2mm), low profile. I know zero about hall effect sensors aside from they are non-contact and use magnets.
Which of these sensors do I need, and am I wasting my time trying to do this?

[Anonymous No.2715027]

>>2715026
Oh, will interface to GPIO on SBC.

[Anonymous No.2715031]

>>2715026
There are analog hall sensors (such are used in ebike throttles for example), and there are digital sensors (such are used in ebike motors).

Read datasheet, fuck around and find out.

[Anonymous No.2715032]

>>2715026
this is a bad idea. If you are required to use this approach for a class then your instructor is clueless or he hates you. An old fashioned contact style switch or a capacitive touch would be much easier.

[Anonymous No.2715038]

>>2715032
It's a personal project. It's for a handheld game, and I'm being picky about the design and throw of one of the switches. Perhaps I should go look through otb stuff a little harder.

[Anonymous No.2715088]

>>2715006
Order "Mechanic" branded solder from aliexpress. You can actually find datasheets for those. I had some of their lead-free stuff with bismuth, a bit mechanically weaker than the normal 60/40 but it's at least as nice to solder with.

[Anonymous No.2715173]

>>2715088
Idk, mechanic is kinda overpriced.
SnBi is interesting, if im gonna make more LEDs, as they are too sensitive to solder with normal solder.

[Anonymous No.2715201]

Has anyone ever DIYed their own smd suction pickup tool? I already bought aquaruim pump for about 5 dollars to mod to a vacuum pump, and I already have the blunt needles, syringes, I think I have an idea on how to build it, and I am curious how people DIYed theirs.

[Anonymous No.2715214]

>>2715201
bit of blue tack stuck on the end of a pencil

simple, cheap, works

[Anonymous No.2715222]

>>2715214
is the blue tak meant to pick up the component? Wouldn't that make it annoying to remove the component from the blue tak
?

[Anonymous No.2715226]

>>2715201
> vaccuum bump fish
If you think you need something like that, you should ask someone with fine motor skills, like your wife who’s probably been doing something like needlepoint for the last 6 hours without beer breaks every 10 minutes.

Or, stop taking half-measures and just put in your preorder for a tesla optimus and it can do all that stuff for you. I’m sure it’s something they think it could be made self aware right now! So hurry.

When you get it, hook it directly up to 4chan so we can help you without your intervention. Thanks.

[Anonymous No.2715247]

My rabbit broke out of his cage at night and roamed around the house wreaking havoc on my cables. I need to rewire some household electronics and thus decided to buy a soldering iron.
I saw this JBC on local marketplace for 40€. It should be good for that right? I'll also need to fix some cold solder joints on a car trip meter screen pcb so I'll preferably buy something with a bit of range the first time

[Anonymous No.2715252]

>>2715247
I'd go with crimped butt splices for fixing up mains wires instead of soldering them.

[Anonymous No.2715276]

>>2715252
Thanks for the tip. I was little unspecific. They're appliance wires. And they're chewed pretty thorough, averaging 1 exposed and possibly shorting conductor per feet.

[Anonymous No.2715284]

>>2715247
JBC make good tools, they're just really expensive. If you can get that station for that cheap it's probably worth it, assuming it's at least 40W or so, and that you can still get tips for it (you probably can).

I would consider just replacing the wires though. With wires that have that nice vulcanised rubber insulation like you get on some kitchen appliances, that's the good stuff.

[Anonymous No.2715299]

Hey /ohm/
How do you manage your custom KiCAD models?
I find it kinda bothersome to add them one by one in the footprint editor and I want them in a seperate folder from the default models.

[Anonymous No.2715306]

>>2715201
Aliexpress is full of them. But I think all you need is a solenoid valve and that's it.
>>2715226
>you cant just get a tool that makes job 10 times easier

[Anonymous No.2715368]

>>2715201
Venturi effect + solenoid
Button toggles solenoid (check valve)

[Anonymous No.2715374]

I have a sensor that is programmed with 8V high level and 5V low level serial. Is there a smarter way to achieve this than switching optocouplers for each level with a serial source? I thought about using level shifters but didn't find any that has a low level voltage output other than 0V

[Anonymous No.2715400]

does anyone make a vacuum solder-sucker tip adapter for the bigass weller soldering irons? ive seen the aliexpress chink specials and they look like garbage due to having low power output. nigger rigging something myself would be trivial... if i had a welder or a lathe.

[Anonymous No.2715402]

>>2715400

[Anonymous No.2715413]

>>2715374
schmitt trigger/comparator buffer with a triggee point st 6.5V

[Anonymous No.2715416]

>>2715413
>schmitt trigger/comparator buffer

easier to just stick a 5.1V zener in series.

[Anonymous No.2715471]

>>2715400
>>2715402

[Anonymous No.2715551]

>>2715471
probably not enough power. i tried desoldering a big SMPS transformer with my t12 iron + 140x series tip + plunger solder sucker. plenty of flux, tinned tip, etc. and i still couldn't quite pull it off. eventually switched to hot air which did work, at the expense of slightly warping and slightly delaminating the board.

[Anonymous No.2715632]

>>2715551
I hope there are T12 tips that are hollow and with a spigot on the other end for a vacuum pump/sucker. Or even better, that but for T245 tips that you can force 200W into.

[Anonymous No.2715675]

fixed a coffee grinder

[Anonymous No.2715677]

>>2715675
What happened? Did you call an amberlamps? Give me the rundown, captain's log style with star date in sidereal time.

[Anonymous No.2715690]

>>2715677
>Half a year ago: the grinder just lost torque and couldn't destroy the beans no more
>5 months ago: I get a replacement mains rated mosfet and replace it on the board
5 months pass, i just never bothered putting it together :)
>Monday: I finally managed to put it together. Plugged it in, started right away... it was not supposed to do that
>Still monday: What the fuck is a triac?
>Today: triac arrived, swapped to the correct component. Plugged it in, nothing.
>Pressed the button, nothing
>I probably shorted the microcontroller to mains with the mosfet
>Just short across the triac with some wire
>It just werks™
And just like that I was able to grind coffee again, thanks for reading my blog

[Anonymous No.2715695]

>>2715690
>microcontroller
What does a coffee grinder need a microcontroller for?

[Anonymous No.2715698]

>>2715695
Motor timer, maybe detecting if it gets stuck and shut down?
It's like a 12 pin so I'm assuming it's not just a 555

[Anonymous No.2715700]

>>2715695
>a coffee grinder need a microcontroller for?

the more parts, the sooner it'll die.
the more money you'll spend.
savage capitalism is so profitable, even the commies practice it.

[Anonymous No.2715702]

>>2715690
You fixed it AND you learned about triacs. Good job, Anon. You get a scratch & sniff banana sticker.

[Anonymous No.2715703]

>>2715698
Probably cheaper than a 555 too, either way it’s definitely lower power so it reduces the low voltage power supply specs to simple resistive dropper levels. Microcontrollers are unironically the cheapest method to implement simple timing and logic. More flexible for modifying an existing design too.

[Anonymous No.2715710]

>>2715306
>>2715368

Thanks I was reading around, and read about people adding a filter to protect any, I assume broken chip being sucked in and possible damaging the pump.Since I was looking at stuff thats commonly used with airbrushes, I was wondering if this will be fine to use as a filter, or is it too restrictive?
>https://www.aliexpress.us/item/3256805533060577.html

[Anonymous No.2715719]

>>2715710
Use a piece of carbon foam sponge in a coupler between tubes.

[Anonymous No.2715752]

>>2715719
>>2715719
hmm I have cotton balls, or should it be carbon foam?

Thanks for being patient, and answering my questions. I am going to look at solenoids and check valves.

[Anonymous No.2715754]

>>2715299
I just put them all in the same folder as the defaults, which I can filter out by sorting by date added, if I ever need to do so. Usually I don't need to because I'm sure to assign custom footprints as default to custom symbols. I'm not yet savvy when it comes to adding tags to custom footprints so they become selectable in the dropdown for adding existing symbols though.

This method is usually a pain for when I update KiCAD, I need to find all my old symbols and footprints and add them to the new version, but this time I installed it with a package manager instead of manually. With any luck it just swaps the core system files over, keeping all my footprints and symbols in the same folders.

[Anonymous No.2715773]

What replacement tips would fit this?

[Anonymous No.2715787]

>>2715752
Cotton is probably more restrictive and will compress over time, but it wouldn't hurt to try.
>>2715773
DSE-T1976-1

[Anonymous No.2715860]

Happy Thanksgiving, niggers.

[Anonymous No.2715910]

>>2715754
protip: prefix your footprint and symbol library names with 00, it defaults to sorting alphabetically, so your own stuff will always appear at the top of the list

[Anonymous No.2716075]

just getting back into electronic projects. I have nothing. Need an ironing station. Looking at this Weller kit for $120?

[Anonymous No.2716098]

>>2716075
Is that soldering station open-loop adjustable power, or closed-loop temperature feedback?

also it's generally worse value than you'd get going for a chinky setup.

[Anonymous No.2716115]

>>2716075
Get a digital station like Hakko FX-888D or Weller WESD51 (direct from the mfr). They both come with brass wool. Forget the helping hands in that pic as it's complete shit. You're better off with a PCB vice or even a lump of Blu-tack. The silicone pad isn't necessary, but it is trendy. For solder, stick with known brands in 60/40 or 63/37 ratio with a flux-core, and avoid lead-free. Use RMA flux or synthetic rosin. Get some desoldering wick too.

[Anonymous No.2716133]

>>2716098
>>2716115

alright in my cart I have

chinesium wick and solder sucker
fume hood
hakko micro cutter
hakko FX888D-23BY
pcb holder, semi-chinesium
lead free solder (sorry sort of a requirement)
rosin
tip tinner

what else?

[Anonymous No.2716139]

>>2716133
>what else?
Light & magnification, Kapton tape, fine-point angled tweezers, hot air station.

[Anonymous No.2716141]

>>2716139
and isopropyl alcohol, contact cleaner, pump dispenser bottle (picrel), and a soft ESD safe brush.

[Anonymous No.2716142]

>>2716141

[Anonymous No.2716147]

>>2716133
>what else?

you're missing 2 of the 3 absolutely-must-have-one-at-all-times hand tools.
- tiny long-nose pliers, with serated grip, not smooth-faced
- wire stripper. i like the one in the pic coz you can adjust it all the way down to 30AWG

[Anonymous No.2716156]

>>2716133
don't forget your safety goggles!

[Anonymous No.2716169]

I wired a circuit wrong but it still kind of works. that has never happened before

[Anonymous No.2716173]

>>2716169
Please explain to the class using a Fritzing doodle drawn with crayons.

[Anonymous No.2716193]

>>2716133
>chinesium wick
Don't chink out on solder wick, if you do be prepared to have to soak it in extra flux.
Also consider an electric desoldering pump, they're worth the slight extra cost if you plan on doing a significant amount of THT desoldering. I also tried out using hollow desoldering needles, they're good when they work but the quality is kinda dubious (plastic handle softens from the heat) and there isn't always room for them between the lead and the hole walls.

>>2716147
>not just using silicone wire for everything that you can strip with your fingernails
ngmi

[Anonymous No.2716200]

How high level is diagnosing and replacing a fractured chip on a smartphone motherboard?
Had a guy fix my phone this way in 24 hours and was impressed. Is it impressive or just normal?

[Anonymous No.2716216]

alright, this is getting expensive but whatever. changed some stuff up.
in cart:

gucci Assembly Specialists breadboard (3M bb OEM)
MENDA pump for IPA
wiha angled pointy tweezers
wiha wire cutter
wiha long nose serrated pliers
wiha tiny snipper
Aven cheap PCB holder
silicone mat
AO701A++ soldering iron (with smoke absorber, which I want) and de-soldering gun combo
1820-10F desolder braid
jumper wire kit
1lb KL100D solder, 0.031", Kester

>>2716156
already own

what else?

>>2716139
idk what desk lamp to get

[Anonymous No.2716218]

>>2716200
It's normal.
Disassemble, 5min
Desolder with hot air gun. ~5min
Clean with desolder braid and lay fresh solder, 5min
Place new chip and blast with hot air; inspect, correct solder bridges, <10min

[Anonymous No.2716221]

>>2716200
>diagnosing
Visual inspection.
FLiR (heat) camera inspection.
If available: self-diagnostics feedback

[Anonymous No.2716228]

>>2716216
>idk what desk lamp to get
Articulating desk lamps with magnification are nice. You can use a jewelers loupe or USB microscope for inspection if you don't like using a magnifying lens.

[Anonymous No.2716232]

>>2716075
These days Chinaman can make a smoldering station for $80... With hot air. Delivered. After tax.
>>2716133
Lemme fix your list
>fume hood
Not needed
>hakko micro cutter
Nibblers from aliexpress made by people who said bad things about Xi for $1 a piece.
>hakko FX888D
I think you're better off getting chinese 936 + hot air combo, or T12 iron instead of original.
>lead-free solder
Get leaded 60/40 or 63/37 from reputable supplier, save your nerves. Lead does less damage to nerves than lifted pad.
LF sucks. Maybe unless you get that SnBi alloy, but rest is just unnecessary pain, leave it for its intended use (i.e. drinking water pipes).

Now, I'd add
>DMM with 4 holes and AA/AAAs
>High CRI LED bulb
>Brass wool
>PVC hook up wire
>Silicone hook up wire
>XLPE hook up wire

>>2716156
This actually, i've cut resistor leads in my eyes, and while chinesium cutters are fresh, they launch shit far and good.

>>2716216
>idk what desk lamp to get
I've bought some random chinese desk "architect" lamp, and it surprisingly had pretty good LEDs. Because originally i wanted to rip them off
For general workbench light I made these, with sunlike chinese led (which have 2 leds there, one violet, one blue, similar effect to seoul sunlike)

[Anonymous No.2716236]

>>2716228
>USB microscope
I use a $55,000 KEYENCE scope at work, wish I could bring it home :(
I don't really like loupes. I'll just wait on it I think.


>>2716232
sorry lead-free is a req, not from my end.
what multimeter to get?

I'll hold off on the nice soldering iron - I'll just get a $10 one right now and see how far it gets me.

[Anonymous No.2716239]

>>2716133
Kester 951 liquid flux. It smells wonderful and will make all of your soldering jobs go magically smooth.

[Anonymous No.2716243]

>>2716236
>sorry lead-free is a req, not from my end.
Get lead-free solder that is 60% tin and rest is trade secret :D
>what multimeter to get?
One with AA/AAAs because 9v are annoying.
I personally use UNI-T UT210E current clamp, but that's not ideal as measuring small currents is complicated, because essentially it picks up earth magnetic field and kinda works like a compass. But works for me because in my previous DMM I kept blowing 20A fuse.

I'd consider $30-50 range, with AAA/AAs and holes (A, mA, V-ohm-etc, GND) , and I'd check internals to see if it has proper protections.

[Anonymous No.2716258]

ok I added in a 951 pen, tip tinner, brass wool, Fluke 107

[Anonymous No.2716272]

dont forget a dc power supply, function generator, oscilloscope, logic analyzer, spectrum analyzer, vector network analyzer, signal source analyzer, and HP 70001A mainframe

[Anonymous No.2716275]

>>2716272
Do we have a recommended power supply and scope for noobs? I don't mind a used ebay unit for a scope.
Also what are the BEST leads in the world? I'm about to buy a nice 90s tektronics bench dmm. but I need leads

[Anonymous No.2716281]

>>2716275
>leads
pomona electronics

[Anonymous No.2716285]

>>2716281
too late I got ProbeMasters

[Anonymous No.2716299]

>>2716075
YES SUPPORT THE US AMERICAN ECONOMY
GODSPEED ANON

[Anonymous No.2716303]

>>2713194
>>2713141
HELLO MENTAL DIARHERRA DATA FARMING SPAM BOTS
UPLOAD MY BRAIN ROT INTO YOUR NIGGER MATRIX ALREADY WOULD (YOU)

[Anonymous No.2716304]

>>2716272
You dont need a lot of that stuff if you have a huntron tracker. Do notmisunderestimate this essential piece of equipment.

[Anonymous No.2716306]

goddamn are there any of these that aren't chinky, I just want light for my bench...

[Anonymous No.2716328]

>>2716306
ikea

[Anonymous No.2716329]

>>2716306
try a Donegan Optical Optivisor, that's what watchmakers use.

[Anonymous No.2716335]

Idea for a general purpose product I could sell to small-scale outfits looking to automate something simple. The items followed by a "?" are items I'm not certain I want to add, lots of feature creep here. Ideally I get the whole thing assembled by JLC so I can skip the soldering, but I don't know if I can ask them to leave footprints unpopulated. I'd make it with KiCAD because EasyEDA is kinda shitty.

My current thinking is to have:
>microcontroller (same kind of specs as a mega328P, though maybe an ESP32 for wireless)
>a pair of half-bridge driver ICs (e.g. IRS2003)
>footprints for FETS of my choice
>big schottky freewheel diodes
>at least one dual op-amp IC
>voltage regulator and caps and stuff
>a bunch of pins to wire buttons and sensing and stuff to

Any further thoughts or suggestions? Or an existing project/product I can look at? I've had two or three requests for custom circuits and this thing could do all of them with the right programming.

[Anonymous No.2716342]

>>2716335
the 328 is ancient and ass, basically no reason to use it in the modern day. If your program doesn't need high clock speeds/sram/etc, stick it on an ATTINY13A or Padauk - if it does, STM32/ESP32/RP2040.
Personally, I would probably go with the ESP32 for the wireless, and flash it with MicroPython.

[Anonymous No.2716344]

>>2716342
>>2716335
forgot to say, but: you could have a footprint that fits a "stepstick" style stepper motor driver module, and have that as a option. Easy to replace and lots of different chips available in that format.
Perhaps a header for a thermistor or thermocouple?
Waveform generator?

[Anonymous No.2716354]

>>2711976
Solder wick is great stuff.
The flux in it evaporates after a few weeks of you leave it out though and then it doesn't suck solder up so well.
Keep it in a ziplock bag or something

[Anonymous No.2716360]

>>2716236
> I'll just get a $10 one right now and see how far it gets me.
It will turn you off to electronics is what it will do, as it burns up your boards and any circuits you try to work on. The only thing those are good for (and barely) is doing butt splices on 16 awg wire when you put in your new car stereo, or doing woodburning projects (don't reuse it for electrical work though.)
Borrow a proper temp controlled soldering station sometime if you don't believe me. This is one of those tools that's 100x better than the cheap version and worth spending money on.
> t. spend waaaay too long using a cheap uncontrolled iron, ruining projects

[Anonymous No.2716367]

>>2716306
If you're me, you curb pick one of these heavy monsters with a round florescent lamp. It's a tool that gets way more use than I thought it would, esp as my near-distance eyesight gets worse.
You can probably find same around you if you check the junk shops.

[Anonymous No.2716385]

>>2716360
what do I buy then?

[Anonymous No.2716405]

do we approve of the pinecil

[Anonymous No.2716408]

>>2716405
>approve of the pinecil

absolutely, as the handle is the perfect size for prostate massages.
leave the Wellers to the breeders.

[Anonymous No.2716421]

i plan on buying one of those chinky function generators and a couple of "BNC to banana jack" adapters so i can use dupont pins, pin grabbers, and alligator clips. do i need to put a 50 ohm terminator between the function generator and the "bnc to banana jack" adapter?

[Anonymous No.2716427]

>>2716421
No, you would just waste power on 50 ohm terminator. It doesn't make sense to use any sort of termination with banana jack connectors because those aren't controlled impedance lines in the first place. Impedance of various cables dangling around is just too random so don't expect to do any high frequency work with that setup beyond few MHz. It's fine for audio and even then you might have issues with noise if you'll be feeding signals into high impedance loads.

[Anonymous No.2716476]

What sort of wire is best for low voltage through hole proto board soldering? Want to grab a spool to go along with my jumpers

[Anonymous No.2716479]

>>2716476
>What sort of wire is best

check every construction site dumpster.
near building completion, you'll find armfuls of telephone and internet cable in them.
yummy 24AWG solid copper wire.
enough for a lifetime.

[Anonymous No.2716517]

>>2716342
>the 328 is ancient and ass
I said "same kind of specs as", because I can't see myself needing more than 32k flash for this. I'd like to use a CH32V003, but I'll have to buy a dev-board and mess about with it first so I'm sure I can actually handle the toolchain on my shitty old OS. An ATtiny1614 or better is also an option, but their availability is bad. 328Ps are still very available, but pricy.
>MicroPython
opinions discarded

>>2716344
Actually I was considering using monolithic motor driver ICs to replace the half-bridges entirely, because they can control lots of things. Step+dir interface wouldn't cut it though, and 5A is pushing it.

[Anonymous No.2716519]

>>2716342
>basically no reason to use it in the modern day
autistic take

[Anonymous No.2716626]

>>2716405
I bought V1 and liked it so much I bought V2.
>>2716476
If it doesn't need to be jacketed, look up "buss wire". If it does, "hook-up wire".
>>2716517
>>MicroPython
>opinions discarded
MicroPython is objectively better for 99% of use cases. On a 32-bit processor speed is rarely an issue, but ease of authoring and then maintaining your software will always be a concern. uPython is easier to write and understand, and has modern conveniences that C++ doesn't. C++ was my first language and probably the one I have the most experience with.

[Anonymous No.2716633]

I didn't see any kind of audio specific thread, but this is still electronics.

So I'm building the audio system for my 80's car and wanted a period correct head unit for it. Found the unit, restored it and it's running great. I still want a 3.5mm jack and bluetooth with it, though. Fortunately the rear of the unit has an aux port for a CD player (albeit as weird 8-pin din) and I have the schematics that tells me exactly what the pinout for it is, and slapping something in there would be fairly easy. The tricky part is most aftermarket bluetooth modules that are ready for install out of the box have their output at line level, and my head unit has a built in preamp that the aux goes through.

Is there a good way to reduce the line level down? I know it would be a bit redundant to drop and then raise it back up, but I'd rather have everything integrated and controlled from the main unit instead of having two units hooked into the amps.

[Anonymous No.2716676]

how the fuck do I shop for used scopes on the ebays

[Anonymous No.2716713]

>>2716633
A simple voltage divider works, you can also buy “line level reducers” that are more idiot proof. I think they’re usually designed to reduce speaker-level to line-level, but should work just as well. You may also need a ground-loop eliminator/isolator (or just use an audio transformer for both purposes). Be sure to mount your Bluetooth module as close to the front panel and without any metal shielding it from cellphones.

/o/ may have its own opinions on how to do this kind of work.

>>2716676
You don’t, you instead go for them at a much smaller scale. Be that on more local 2nd-hand sites, garage sales from the widows of radio hams, or by snooping about your uni.

[Anonymous No.2716730]

>>2716713
>line level reducer
Huh, this might be the most braindead method. I'll need to look a bit further into that and attempt to figure out what my exact level should be according to the schematic. Honestly I'm a bit new to reading schematics of this complexity as well to audio engineering in general, so I want to make sure I get this right without blowing it up. After volume control it goes through two bilateral switches as gain selectors, and then the amp transistor for pre-amp output. Would anyone mind looking at the schematic and checking my ass before I do this?

https://www.mediafire.com/file/i9sy7i8lsq4hdwx/kenwood_krc-999_service_manual.pdf/file

Genuinely not dolphin porn.

[Anonymous No.2716747]

>>2716730
"13 Pin Bluetooth Aux Adapter"
Wonder if that would work.

[Anonymous No.2716750]

>>2716747
That's for a newer kenwood.

[Anonymous No.2716805]

>>2716730
>attempt to figure out what my exact level should be according to the schematic.

they might specify such things on 1950's radio schematics, but not modern stuff.
tho, they might have a separate specifications table showing expected input and output levels.
but there's no need. you can just use a stereo pot and crank it up until it sounds right.
just remember to start at zero volume and go up slow. use 10-100K, linear or log taper.
(note the pic is showing the back of the pot - when you look at it from the front, ''input'' and ''ground'' are reversed)

and dont be such a pussy.
nothing's gonna die unless you do dumb shit like blast 10V signals into an AUX or CD input.

[Anonymous No.2716819]

>>2716354
> solder wick should be kept in a ziploc or something
No argument
> because the flux evaporates
I have 30 year-old solder wick that’s been left in drawers and it still works fine.

[Anonymous No.2716828]

>>2716713
should I spend $100 on an old nice analog scope, or spend $200 for a ultra-cheap digital one?

[Anonymous No.2716829]

>>2716805
My autism is making me hyperfocus on the specifics, especially given that this deck was a pain in the ass to get a hold of for a reasonable price (niggers on ebay want 2k for this fucking thing and it ain't worth that goddamn much). I guess I'll just dump the line audio directly in and see how it sounds, then go from there.

[Anonymous No.2716834]

Anyone know about ZVS drivers?
This thing used to draw low amps unless you powered something with it.
Now it pulls 20A at 3V and the mosfets warm up hot.

[Anonymous No.2716863]

>>2716828
Generally I'd only buy a digital scope if it's >50MHz and 4 channels. 20MHz 2 channel scopes aren't worth it. But CRT scopes without digital storage capture (i.e. can only view repeating waveforms) are also kinda shitty, especially if you don't have a USB logic analyser or specifically need to capture analogue waves.

>>2716834
My guess is the FETs are damaged. To see if they're leaking current when they're supposed to be turned off, try desoldering the gate pullup resistors and powering it up to see how much current it draws. If it's basically zero then at least the FETs are turning off properly, if it's still like 3A (or higher) then the FETs are fucked. I'm not sure what else could cause such a high quiescent current.

[Anonymous No.2716885]

alright lads the purchasing spree continues.

Aquired:
SOLDAPULLT
Aluminum handle brush
Tweezers
Iron
PCB holder
IC puller
Used benchtop multimeter
test lead kit
IPA pump
silicone mat
desoldering braid with rosin
951 flux pen
tip tinner
brass wool
solder


what wire stripper should I get? what else? should I waste $60 on a amazon Chinese power supply?

[Anonymous No.2716886]

>>2716828
depends what you need. those $30 DSO-138 kits work fine if you're just messing around with low frequency (<100kHz) stuff.

[Anonymous No.2716897]

>>2716885
get a fiberglass pen
good for taking the solder mask off a trace for installing a bodge wire

[Anonymous No.2716899]

>>2716886
I'm eyeing a $180 DSO2C10 right now. It will be my first scope, I think a simple 100mhz 2-channel is more than enough for me.

[Anonymous No.2716902]

>>2716899
that's a good price, go for it
just make sure you aren't gonna quit before it arrives lmoa

[Anonymous No.2716910]

>>2716902
there was a BF sale; got this for $160 shipped. Seems to be a solid unit and will be more than enough for my purposes.
>quit
Hah, I have a gizmo that I'm going to be selling, it will sell maybe 20 units total, profit per unit is like $5? So yeah I'm spending a thousand bucks on a work station setup for that lol

[Anonymous No.2716912]

>>2716885
Picrel is the brand and model wire stripper I’ve been using for over 30 years. Everything else stopped working or was generally shit. I inherited it from my father. Of course my handle has the letters worn off by the time I got it.
It’s flexible, works well and is reliable.

[Anonymous No.2716916]

>>2716912
I do wonder if thermal wire strippers work well

[Anonymous No.2716918]

>>2716885
> waste money on a first power supply?
No, A power supply is the quintessential first project for any non-larper. Make multiple on an as-need bases.
If i come down to your work area and I see some noisy, unisolated, fire hazard of a chinese power supply, I’m not going to think very highly of you.

[Anonymous No.2716920]

>>2716916
> thermal wire strippers
Never heard of that. I sometimes use teflon coated wire for really fine work because when you’re trying to solder an insulated wire to a tiny <1mm pad with a very small bit of the conductor exposed, PVC wire insulation will shrink and melt back exposing far too much conductor, melt into other conductors, and generally look like dogshit.

[Anonymous No.2716923]

>>2716910
Seems reasonable for messing around.

If you want to diagnose digital shit like USB 3 speeds though, you literally need like a $1 million scope.

[Anonymous No.2716924]

>>2716920
I'm looking to pick up HotWeezers, apparently it's used in aerospace a lot when you aren't allowed to cut strands when stripping wire.

[Anonymous No.2716932]

>>2716924
You’re not even allowed to nick, scuff, or scarify strands. I pull out lighting fixtures where the wire just snaps off where the previous dumbass electrician nicked the wire.
Copper wires are notch sensitive.

[Anonymous No.2716936]

>>2716918
my diy psu is an lm2596 module with cc/cv pots soldered to it via wires, crammed in a box with a panel volt/amp/watt/watt-hour meter, and a barrel jack on the back
the panel meter was designed to be self-powered, i broke a trace in it so i can power it separately from its sense wire, but below a certain voltage it flashes the display because it thinks it's going into brownout, so i added a deadbug attiny13 to "push the button" when it detects the backlight flashing to stop it flashing. also the refresh rate is awful.

>>2716924
i use silicone wire for everything, hot wire stripping wouldn't work but that shit is so soft i can just use my fingernails
wonder what ptfe insulation is like to strip, i've never used it

[Anonymous No.2716943]

>>2716863
Yep its the mosfets stuck on. I wonder why it did that

[Anonymous No.2716945]

any pro tips for selling electronics and making it look professional?
>small round QC sticker
>ESD bag
>...?

[Anonymous No.2716947]

(I mean like self-designed/soldered electronics)
>>2716945

[Anonymous No.2716957]

>the scope I just ordered has a hacking scene, can enable AWG and get a 50mhz boost for free
https://www.eevblog.com/forum/testgear/new-hantek-dso2x1x-models/msg3559217/#msg3559217
NEAT

still some left at the $160 price btw https://www.amazon.com/Hantek-Oscilloscope-DSO2C10-Bandwidth-Sampling/dp/B08MDRF6L3/

[Anonymous No.2716974]

>>2716945
the bog standard qc sticker is basically a red light telling everyone your product is chink shit

[Anonymous No.2716985]

>>2716385
I have a Weller Soldering Station, older version of pic related, which is a US toolmaker. There are a ton of models like these, including china knockoffs that are cheaper, but the important part is that it needs to be temperature controlled. The tip will heat faster and maintain a consistent tip control. There will be a control box that plugs in and a dial or some way to set temp.
Someone will jump in now with all the AliE options; actually surprised there's not something in the general.

[Anonymous No.2716988]

>>2716476
You can get these little 24AWG solid wire kits from AMZ, etc. Comes in like 5 colors. Get that for through board, and same of stranded for stuff where it needs to bend. 24AWG also works well with breadboards.
>>2716479
Bell wire I've found is 20AWG and won't easily work with breadboards. Otherwise solid advice; I've a big chunk of 6-wire thermostat wire I just tore down and spooled by color.

[Anonymous No.2717062]

>>2716924
>I'm looking to pick up HotWeezers

i have something similar.
it's a hot stinking smoky mess.
maybe it requires some specialized wire, but on regular old wires it's awful.
burning insulation makes your house smell awful, and the melted plastic ends up stuck to the copper.

[Anonymous No.2717100]

Is the Rigol DS1054Z cheapest 50mhz 4 channel oscilliscope? If there is an actually good clone thats recommended on aliexpress I would like to know.

I just know if I go with 2 channel, I'll regret it, and wish I went with 4 channel. Unless buying 2x 2 channel oscilliscopes being cheaper then 1x 4channel is a thing, probably not a thing, and doesn't make it equivalent.

[Anonymous No.2717149]

>>2717100
get a 2 channel

>>2717062
hmm well there is still time for me to lose the auction

[Anonymous No.2717173]

>>2717100
wtf is the point of 4channel

[Anonymous No.2717188]

Can anyone identify this oled module? I can't seem to find the data sheet for it. I think it uses the ssd1303 controller, but I might be wrong.

[Anonymous No.2717189]

>>2716936
> PTFE insulation
teflon insulation is hard to strip off.
Normally, other types of insulation will split away if you nick them, but teflon is a lot tougher. The best way I’ve found to strip it is to use the backcut method where you place your knife at the end of the wire, on top of the conductor, and cut backwards and up towards the outside of the insulation. This used to be a standard practice of stripping wires back in the day. See picrel.

Olfa knives are great for this, but they have to be sharp, so I sharpen them to do the job. I know what you’re saying, “they’re already sharp”… no, you don’t understand… they need to be sharper than that to do a good job of cutting PTFE. The steel used in olfa knives seems pretty good at getting a good edge. As one might expect.

[Anonymous No.2717190]

>>2717189
What if I build a tiny pencil sharpener for ants and stick the PTFE wire in it?

[Anonymous No.2717199]

>>2716985
> temperature control
I think this is a meme. Nobody needs temperature control, I’ve soldered 10s of thousands of joints without it. Temperature control doesn’t even actually work the way you think it does.

It was the same problem with people saying that you should use brass wool to clean your tip instead of a wet sponge because “cooling the tip so fast causes the iron plating to crack” or some nonsense like that. The brass will suck the heat out of the tip at the thin iron plating level much faster than the wet sponge due to the leidenfrost effect, which is why blacksmiths often quench things in oil rather than water.

It’s the same thing when you touch the tip of the iron to something and it “wets” the connection. This is all in the thermal mass of the tip, and it’s dependent on the time the tip is in contact with the joint and have very little to do with the meme temperature control system.

If you’re a literal retard, and you’re holding the iron on the joint for 20 minutes, then yeah, you should get a temperature controlled iron.

Or, if you deal with very low or very high temperature specialty solders, then maybe you want an adjustable temperature. Again an “active, real-time, microprocessor-controlled dual-sense feedback loop” system is unnecessary.

A standard 27 watt electronics soldering iron is actually temperature controlled—but it’s intrinsic to the design. It reaches an equilibrium temperature because when it gets hot, it dissipates heat at the same rate it’s putting it in.

What temperature do you even set the thing at?Certainly not the melt temperature of the solder. This will make cold solder joints. What you do with a regular soldering iron is it reaches it’s equilibrium temperature higher than that of standard 60/40 solder, and as soon as you touch the joint it equalizes that temperature to be only slightly above the solder melt point. Elapsed time, < one second.

[Anonymous No.2717254]

Can anyone think of why the green and blue channels of this circuit would be so much less efficient than the red? I tested them channels individually with my bench supply. The schematic regulates each channel at 40 mA, which I verified by measuring the voltage drop across R10,11,12,13,14,15 which showed 1.9V to 2.0V.

Red: 3.7 V, 180 mA input ==> 40 mA output @ 13.3V ==> 80% efficiency
Green: 3.7 V, 340 mA input ==> 40 mA output @ 19.3V ==> 61% efficiency
Blue: 3.7 V, 360 mA input ==> 40 mA output @ 20.3V ==> 61% efficiency

I was expecting closer to 80% efficiency as the data sheet shows (and as the red channel shows.)

https://www.diodes.com/assets/Datasheets/AP3019A.pdf

My inductor is rated at ~1A so I don't think it's saturating?

[Anonymous No.2717259]

>>2717199
I've used both. Non controlled is trash. Try both, buy one.

[Anonymous No.2717285]

>have rotary phase converter that is labeled 240v 3 phase.
>each leg outputs 140v

is it wired for 480 or is this standard?

[Anonymous No.2717310]

>>2717254
Are R10-R15 all of the same value? The loss path is as follows
>inductor losses
>internal switch losses
>internal diode losses
>LED differential resistance loss
>R10-R15 loss
>sense resistor loss
>output capacitor loss
Power is being wasted on something in that list. This is essentially a boost converter so same equations apply.

[Anonymous No.2717321]

>>2717254
Green and blue need higher voltage than red.

[Anonymous No.2717323]

>>2717310
I just raised the input voltage to 9V for the hell of it.

Red: 9.0V, 72mA input ==> 40mA output @ 13.7V ==> 85% efficient
Green: 9.0V, 108ma input ==> 40mA output @ 20.4V ==> 84% efficient
Blue: 9.0V, 110mA input ==> 40mA output @ 21.0V ==> 85% efficient

The efficiency loss @ 4.7V input on the green/blue drivers is occurring inside the IC, judging by how hot it gets (uncomfortably hot) relative to the 4.7V input red driver (cool to the touch.) The resistors and inductors are all cool to the touch.

I have no idea why the efficiency is so bad at 3.7V. The data sheet suggests that it's capable of ~80% efficiency at 3.7V.

[Anonymous No.2717339]

>>2717199
I find a few benefits of a temperature controlled iron.
Firstly, when I’m hand-soldering a D2PAK or other thermally massive joint, having more than 50W and an iron that doesn’t dissipate most of its power via convection is a flat requirement. High-power non-temp-controlled irons are large an unwieldy by necessity, and at soldering temperatures you necessarily lose a lot of your power input to thermal regulation. Curie-point and to a lesser-extent PTC irons don’t have this issue.
Secondly, I can set my temperature up to over 400C when I’m wanting to solder 8awg or whatever to store some energy in the thermal mass of the iron, or I can set the temperature down to under 200C for heat-shrinking or plastic welding or whatever.
Thirdly it heats up in like 10 seconds, it’s just convenient. My cartridge tips can also be hot-swapped with ease, which you don’t get on non-temp-controlled irons.

[Anonymous No.2717343]

>>2717323
...and raising the input voltage to 5.0V gets me R/G/B efficiencies of 83%/80%/80%, respectively. Looks like this IC is pretty terrible for 3.7V single cell operation. How the fuck is the data sheet so inaccurate.

[Anonymous No.2717413]

>>2717254
High voltage ratios are less efficient, plus at low voltages you’re less able to turn your FET on hard to avoid ohmic losses in the FET, assuming it’s a FET-based converter.

[Anonymous No.2717421]

>>2717343
Chinese clone/rebadged reject?
Normally you don’t run anything near it’s min or max ratings. If you compute a resistor is going to dissipate 1/4, you DON’T use a 1/4 resistor.

[Anonymous No.2717426]

>>2717339
> soldering, just the tip
The reason why hakko irons are so well respected is because the tips are this massive slug of copper with more specific heat capacity than Picasso’s got paint.

Unless you get a chinese clone, then it’s likely some kind of metal they stripped out of a decommissioned nuclear reactor, melted down, and sold to the north american and european market.

[Anonymous No.2717428]

>>2717426
Those are fine so long as the thing you're soldering has significantly less thermal mass than the tip itself.

[Anonymous No.2717474]

allow me to interrupt for a moment:

[Anonymous No.2717477]

>>2717474
https://www.aliexpress.com/item/1005006147448779.html
link for anyone else interested, they're like $8 for non-lard sizes, shipping is another $5 though it depends on where you live

[Anonymous No.2717482]

>>2717474
>>2717477
If I order the snib snab shirt, the ADL will declare it a symbol of hate and send the FBI to my house. Is 2XL lard size?

[Anonymous No.2717492]

>>2717482
>Is 2XL lard size
No, the price only jumps up at 3XL and above. Though as always, double check the chinky size chart. I just ordered a medium because the shoulders of a small are too narrow.

[Anonymous No.2717498]

Is there a simple and safe method to check if there's electricity in home net and if not "flip the switch" of a generator?

[Anonymous No.2717522]

>>2717498
could switch the genny with an NC relay powered off mains, or simply get a better one that has that functionality built-in

[Anonymous No.2717529]

>>2717522
NC relay is nice but id like to have configurable timer after current drop which means I need something like attiny. But how do I check if there's current in the main net using a custom circuit safely? I can't change the generator, it's not mine but for my parents.

[Anonymous No.2717539]

>>2709490
Hi! I want to make one of those sunrise lamps that slowly increase luminosity until I wake up. I wamt to use two timer/countdown chips, which I would set with a potmeter each, and some sort of circuitry to connect them to the lights. I vaguely remember building something conceptually similar with my dad once, two vharging capacitors would set off two transistors in rapid succession, I want to make it work much slower this time.
This is the rough function diagram of the circuit I imagine. "Timer1" would gradually let more current or voltage through as it counts down, eventually tripping the transistor and thus activating timer2, which would perhaps directly increase the current through the lights.
Is that how these things work? How would you do it?

[Anonymous No.2717545]

>>2717498
The legal way assuming the gen is connected to the house would be an automatic transfer switch. Since while the gen is running the house cannot be connected to the grid.

[Anonymous No.2717556]

>>2717539
If you want to build functional device as quickly as possible then just use arduino. If you want to do this to learn analog electronics then you need to build a couple of subsystems
>alarm clock
>envelope generator
>dimmer
For clock you could do the Ahmed/terrorist style and just use existing device. Then you need a way to generate envelope. Most basic way is to use resistor capacitor combination and use that exponential signal to drive dimmer circuit, then add some digital logic to tweak desired behavior. It's a lot of components so replacing everything with a microcontroller is an easy way to solve this.

[Anonymous No.2717562]

>>2717539
Seconding doing this with arduino, either off the back of a off-the-shelf clock, or integrating clock into arduino itself.
What you're describing is some sort of slow RC circuit, but would probably look something more like this in practice.

[Anonymous No.2717568]

>>2717539
Here you go. Appears this works by switching AC power to switch, which you'd do with a relay run by the clock.
https://pindiagram.blogspot.com/2012/02/20vac-60-watt-sunrise-lamp-circuit.html

[Anonymous No.2717569]

>>2717421
bought these off LCSC so probably not counterfeit.

[Anonymous No.2717577]

>>2717474
>>2717477
Why would you pay for becoming a public billboard for an awful company?

[Anonymous No.2717595]

>>2717568
This is brilliant. At first I’m like how is he getting around the mosfet’s body diode effect or is he driving the lamp at 30 watts? Then I saw the bridge rectifier on the mains.

[Anonymous No.2717687]

Some nonsense I bought came with a ribbon cable that's too short. Assuming I can obtain new cable that's the right length+pitch (since it's the only thing that's labeled) which would make more sense:
>try to jig pick the old connectors and reuse them, assuming I don't forget the layout.
>Buy new replacement connectors
>Buy new connectors but to plug the old cable into
I have the strand size and rough pitch but I can't really identify the standard/connectors. And wouldn't know where to buy a handful that isn't $2 each.
>14 strand, 2 row, .05" 1.27mm pitch, 30awg

Also from my sloppy misunderstanding of signals, twisted pairs does fuck-all if the pairs are not carrying a similar signal right?

[Anonymous No.2717689]

>>2717687
twisted pairs are mostly for reducing vibrational inductive noise, and they can work with balanced (+/-) and unbalanced (sig/gnd) lines.
but if you're doing RF stuff, they don't even come close to coax

[Anonymous No.2717700]

>>2717689
I don't even know the arrangement of the pinout signals but wanted 'some' shielding for it. It's basically just ethernet signal wire but I need it to traverse inside a case further than the flat cable I was given. It's not terribly important but twisted pairs with ribbon flats was an option when I did my initial look for ribbon cable.

Though I suppose if I'm making this myself, I could find some shielding tube, but also probably doesn't matter for 1ft of cable.

[Anonymous No.2717707]

A surface mount capacitor fell off my vacuum cleaner, It doesn't have any markings on it or the board that indicate its capacitance. I tried taking a reading with a multimeter, and I think it's short, maybe the stress that weakend the solder joints also broke it? Is there a way to reasonably guess what capacitance it was?

[Anonymous No.2717713]

>>2717707
It might run fine without the cap, so try that first.

[Anonymous No.2717721]

>>2717713
The low battery lights will turn on when I plug it in, but it won't turn on no matter how long I leave it charging. I guess the batteries could have failed and the capacitor have been irrelevant. I'll try measuring the batteries.

[Anonymous No.2717733]

>>2717721
Otherwise you might need to short the former terminals of the cap.

[Anonymous No.2717747]

>>2717556
>>2717562
>>2717568
insightful and effortful posts, thank you very much! I'll study the diagrams in detail over the coming days
arduino would feel like cheating a bit, or at least buying my way up, currently looking into digipots and digital rheostats to run off of a cellphone/laptop with some sort of script, perhaps I'll know more thomorrow after talking to the boomers at the electronics store

[Anonymous No.2717749]

>>2717577
A: it's cheap
B: it was the only semiconductor manufacturer shirt i could find
C: they make some decent chips
D: snibbedy snab

[Anonymous No.2717753]

>>2717749
You could have just said you're a tranny and left it at that.
YWNBAW.

[Anonymous No.2717756]

>>2717749
>C: they make some decent chips
lol

[Anonymous No.2717760]

Are pic related oscillioscopes worth using for anything?
I don't work much in time domain anyway, mostly curious if these are useful or just doorstops. Assumes buyer can print their own case ofc.
>>2717747
>or at least buying my way up
I'm betting that a $2 nano +$2 OLED screen will end up being cheaper than discrete, having done this excercise a couple times already on projects. Just the flexibilty to program vs. swapping parts is pretty useful, absent the cost.
The part the makes your project complex is the clock / alarm part. If you get rid of that, discrete vs. arduino is probably same.

[Anonymous No.2717773]

>>2717760
I found it very useful early on, before I committed to my 100MHz scope, and I still find it useful for portable applications. Solder a 9V battery connector to a power jack and you can take it out in the middle of a field.

[Anonymous No.2717785]

>>2717747
>insightful and effortful posts, thank you very much! I'll study the diagrams in detail over the coming days

dont be a silly goose.
it's 2023, you dont use arduinos and relays for this kind of thing.
we all IoT now.
you can get this wifi smart switch at Amazon for just $18 on Cyber Monday.
you can program it to do 1000 things, including bringing the lights up slow on a schedule.

[Anonymous No.2717787]

>>2717760
Single-channel makes it really difficult to properly trace a circuit, and the DC offset is kinda shit. Depends on what you're using it for I guess, but I consider 2 channels and a low DC offset a bare minimum.

[Anonymous No.2717791]

new benchtop tek dmm arrives tomorrow, sweet.
I'm a mechE major - so I'm slightly unfamiliar with EE stuff. Is there a cheap 'gauge' equivalent for testing DMMs? Like a 1" gauge block for checking a caliper. I assume I'm looking for a NIST traceable resistor or something.

[Anonymous No.2717810]

>>2717785
but I don't want any more aspects of the antichrist in my house, do I?

[Anonymous No.2717812]

>>2717760
you are probably very much right
I still hope to find some cheap&easy discrete timer thing (I thought they made them in IC box form), but if I can't, then I'll go ahead and overkill it with some sort of controller, that should be doable enough

[Anonymous No.2717814]

>>2717791
not that I know of, you generally don't need that kind of accuracy
but a 1% tolerance resistor should be within 1% of its written value, if you insist on a standard

[Anonymous No.2717830]

>>2717707
> Is there a way to reasonably guess what capacitance it was?
Not really, but there could be a couple hints: if it's smack-dab right on the pins of an IC, it's probably a 100nf bypass cap. If it's right across the board's power rails and it's big, it might be ambiguously "big" which for SMD caps means like 1-10uF.

[Anonymous No.2717849]

>>2717814
true, I suppose in electronics you're already assuming ~5% variability in most cheap components anyways (outside of like clocks)

[Anonymous No.2717871]

>>2717773
> Portable
That's a good point.
>>2717785
Anon could get an arduino with wifi and use that to pull time while he's at it.
>>2717810
This.
>>2717791
Aside from >>2717814 (accuracy) there's no way to "tune" the cheap DMM anyway. The entire purpose of a gauge block is to calibrate the caliper, for example. There's no calibrating a cheap DMM anyway.
> t. mechE as well

[Anonymous No.2717897]

>>2717791
Nothing cheap. Professional calibration centers use hermetically-sealed, thermally-insulated machines with built-in ovens that keep the parts at a constant temperature to achieve .001% tolerances and <2ppm/year drift.
If you just want to verify that your machine is good (say, you bought it used), you can get some (relatively) cheap 0.1%/0.01% components, one for each range for each mode, off Digikey or Mouser.

[Anonymous No.2717899]

>>2717791
There are absolutely voltage and resistance standards. But they are pretty pricy and you need to get them to a calibration house and back without disturbing them if you want to keep your 8.5 digit accuracy. See Marco Reps’s YouTube channel for some A-grade instrumentation autism, then once you’ve learnt enough you can design your own somewhat flawed LTZ1000 standard.

For most people though, they’ll just take their measurement devices down to a calibration specialist who himself has some nice standards to calibrate your hardware with. Some high quality precision hermetic resistor packages might be relatively cheap for the calibration you can get out of them.

>>2717812
You can make it less overkill by using the cheapest shittiest MCU you can possibly find. The ATtiny10 is particularly shitty to work with, while those one-time-programmable 3c Padauks are pretty up there too.

[Anonymous No.2717938]

>>2717760
I love the old IBM 8514 VGA font they’re using.
If it has an x/y mode it might be useful as a kind of advanced VU meter, and moreso if it has an X/Y more.

[Anonymous No.2717941]

>>2717760
I love the old IBM 8514 VGA font they’re using.
If it has an x/y mode it might be useful as a kind of advanced VU meter.

[Anonymous No.2717945]

>>2717941
>x/y mode
reminder
https://www.youtube.com/watch?v=J1ylMJwfLmM

[Anonymous No.2717952]

>>2717812
Ahmedanon with the alarm clock had the right idea. Go to goodwill or something and pick one up, and use it as the base.
It’s got a
transformer/psu,
the colon will flash in seconds (there’s your clock)
battery backup
it gets it’s timebase from the 60 Hz line which is way more accurate than some built-in mems oscillator. And by “way more” I mean the built-in osc is absolute garbage, it could gain/loose a minute per hour
and other goodies you can take advanage of.
you can key off the alarm signal (some have two alarms) and all the setting logic.
If not, you can have the microcontroller read the digits. Note that they are likely cycle each digit in a loop, so you have to read the digit ‘strobe’ with a gpio line. Or interrupt. whatever.

[Anonymous No.2717964]

>>2717945
I was thinking of the pioneer SD-1000
Got a fuckin’ oscilloscope built into it.
Something every device needs.

https://www.youtube.com/watch?v=cC8aqfAWupg

[Anonymous No.2717990]

>>2717964
damn why are the cool obsolete tech things always $1000+ on eBay. I want one. same with an Atari video music

[Anonymous No.2717992]

you can buy new crt oscilloscopes from the chinks
they look like shit

[Anonymous No.2717995]

>>2717992
I thought the last CRT factory in the world closed in India in 2011?

[Anonymous No.2718050]

>>2717474
awwww sheeeeeeeet

[Anonymous No.2718093]

getting tired of waiting 3 weeks for chink PCBs to arrive and then being faced with a retarded design problem on my behalf that renders them basically worthless. i've seen people do DIY 2 layer copper clad with good results, to the extent that even 0.5mm pitch parts work. given that these DIY copper clad PCBs don't have solder mask, would solder paste + hot air or a hot plate work?

[Anonymous No.2718111]

>>2717995
and i thought they learned plumbing but they surprise us again and again

[Anonymous No.2718117]

>>2718111
Spotted the Big Toilet shill. How much porcelain are they paying you?

[Anonymous No.2718134]

does this check out, or am i retarded?

[Anonymous No.2718159]

>>2718134
Looks ok at first glance.
Some might say you should put the LED on the collector side.

[Anonymous No.2718378]

>>2718093
Works fine, just use a lot of flux. How fine you can go depends on how you're exposing your etch resist film, specifically, it depends on the DPI of your printer (if using transparencies) or the resolution of your resin printer (if exposing directly). Double-sided boards are a little tricky because you need to line up both sides perfectly, and you don't have access to plated through holes, though you can sort of do those with PCB rivets. If you're in the US, I recommend just using OSHPark if you don't need a board literally today, they fab boards in-country and a reasonably-priced expedited service is available.

[Anonymous No.2718385]

>>2718378
Oh, and it also depends on what etchant you use: the more aggessive the acid, the less undercutting (etching traces from the side) you'll have.

[Anonymous No.2718403]

>>2718093
Generally solder mask isn't needed, but if you've got a QFN or other package with tight tolerances and a thermal pad it's hard to guarantee that there isn't solder leakage between pads. The extra thickness of the solder mask makes it more likely that the solder stays in place, and it also glues down thin traces to make delamination less likely.

If you're routing boards, you can get/make one of those spring-loaded bits and mill your own solder mask.
If you've got a laser cutter then it's no harder to burn away solder mask than it is to burn away etch resist, so long as you spin-coat it nice and thin first. With the right software (I wrote my own) you can get a laser width compensation that can account for the shitty beam width of diode lasers and even some over-etching. Though laser systems still need CNC drilling to make an accurate 2-layer board, and alignment isn't wholly trivial, so I still consider it less convenient than milling.
If you're using an MSLA 3D printer or transparency photomask setup, you technically can selectively cure a solder mask, but I find it's tough to get it to stick onto the board and not stick onto the mask transparency (maybe an FEP film between them will help), also alignment is a pain and a good contrast ratio can be tough to achieve.
If you're doing toner transfer then there isn't any easy way of getting a solder mask, without going to transparency photomasks.

[Anonymous No.2718435]

>>2718117
not enough, times are tough. i don't have enough porcelain to build the tank yet so i have to use my garden hose.